Implement machine learning models in your iOS applications. This short work begins by reviewing the primary principals of machine learning and then moves on to discussing more advanced topics, such as CoreML, the framework used to enable machine learning tasks in Apple products. Many applications on iPhone use machine learning: Siri to serve voice-based requests, the Photos app for facial recognition, and Facebook to suggest which people that might be in a photo. You'll review how these types of machine learning tasks are implemented and performed so that you can use them in your own apps. Beginning Machine Learning in iOS is your guide to putting machine learning to work in your iOS applications. What You'll Learn Understand the CoreML components Train custom models Implement GPU processing for better computation efficiency Enable machine learning in your application Who This Book Is For Novice developers and programmers who wish to implement machine learning in their iOS applications and those who want to learn the fundamentals about machine learning.

Dive into the world of developing for all of Apple platforms with SwiftUI, Apple's new framework that makes writing applications faster and easier with fewer lines of code. This book teaches the basics of SwiftUI to help you write amazing native applications using XCode. For developers already familiar with ReactNative, this book reviews the declarative, state-based DSL that manages the UI and updates it automatically will feel just like what they're used to. You'll see how SwiftUI reduces the number of lines of code required to achieve the same effects by over 60% and provides a much better experience. Like the announcement of Swift in 2014, SwiftUI is expected to fundamentally change the way developing programmers approach coding iPhone and iPad applications. This book examines how SwiftUI lowers the entry barrier for developers to write amazing cross-platform applications for iOS and iPadOS as well as WatchOS, Mac OS, and TVOS. What You'll Learn Write code in the new SwiftUI syntax Combine views to arrange them for an application Add gestures and controls to an application Who This Book Is For Anyone who wants to learn to develop apps for the Mac, iPhone, iPad, and Apple Watch using the Swift programming language. No previous programming experience is necessary.

Create a fully featured application that's both sophisticated and engaging. This book provides a detailed guide in developing augmented reality games that can take advantage of the advanced capabilities of new iOS devices and code while also offering compatibility with still supported legacy devices. No programming experience is necessary as this book begins on the ground floor with basic programming concepts in Unity and builds to incorporating input from the real world to create interactive realities. You'll learn to program with the Unity 2017 development platform using C#. Recent announcements of increased AR capabilities on the latest iPhones and iPads show a clear dedication on Apple's part to this emerging market of immersive games and apps. Unity 2017 is the latest version of this industry leading development platform and C# is a ubiquitous programming language perfect for any programmer to begin with. Using the latest development technologies, Beginning iOS AR Game Development will show you how to program games that interact directly with the real world environment around the user for creative fantastic augmented reality experiences. What You'll Learn Download assets from the Unity store Create a scene in Unity 2017 Use physics and controls on mobile devices Who This Book Is For Beginner programmers and/or people new to developing games using Unity. It also serves as a great introduction to developing AR games and educators teaching the subject at high school or higher levels.

Is Windows giving you pause? Ready to make the leap to the Mac instead? There has never been a better time to switch from Windows to Mac, and this incomparable guide will help you make a smooth transition. New York Times columnist and Missing Manuals creator David Pogue gets you past three challenges: transferring your stuff, assembling Mac programs so you can do what you did with Windows, and learning your way around Mac OS X.Learning to use a Mac is not a piece of cake, but once you do, the rewards are oh-so-much better. No viruses, worms, or spyware. No questionable firewalls, inefficient permissions, or other strange features. Just a beautiful machine with a thoroughly reliable system. Whether you're using Windows XP or Vista, we've got you covered. If you're ready to take on Mac OS X Snow Leopard, the latest edition of this bestselling guide tells you everything you need to know: Transferring your stuff -- Moving photos, MP3s, and Microsoft Office documents is the easy part. This book gets you through the tricky things: extracting your email, address book, calendar, Web bookmarks, buddy list, desktop pictures, and MP3 files.Re-creating your software suite -- Big-name programs (Word, Photoshop, Firefox, Dreamweaver, and so on) are available in both Mac and Windows versions, but hundreds of other programs are available only for Windows. This guide identifies the Mac equivalents and explains how to move your data to them.Learning Snow Leopard -- Once you've moved into the Mac, a final task awaits: Learning your way around. Fortunately, you're in good hands with the author of Mac OS X: The Missing Manual, the #1 bestselling guide to the Macintosh.

Moving from Windows to a Mac successfully and painlessly is the one thing Apple does not deliver. Switching to the Mac: The Missing Manual, Snow Leopard Edition is your ticket to a new computing experience.

Examine how to keep iOS devices safe in the physical world, including creating company policies for iPhones; assessing and defending against cyber vulnerabilities and attacks; working with preinstalled as well as third party tools; and strategies for keeping your data safe including backing up and screen locks. Managing and maintaining iPhones and iPads in a corporate or other business environment inherently requires strict attention to security concerns. Managers and IT professionals need to know how to create and communicate business policies for using iOS devices in the workplace, and implement security and forensics tools to manage and protect them. The iPhone and iPad are both widely used across businesses from Fortune 500 companies down to garage start-ups. All of these devices must have secure and monitorable ways to connect to the internet, store and transmit data without leaks, and even be managed in the event of a physical theft. Pro iOS Security and Forensics covers all these concerns as well as also offering tips for communicating with employees about the policies your business puts in place, why those policies are important, and how to follow them. What You'll Learn Review communicating policies and requirements for use of iPhones Keep your iPhone safe in the physical world Connect to the Internet securely Explore strategies for keeping your data safe including backing up and screen locks Who This Book Is For Managers and IT professionals working in a business environment with iPhones and iPads.

Unlock the secrets of the Terminal and discover how this powerful tool solves problems the Finder can't handle. With this handy guide, you'll learn commands for a variety of tasks, such as killing programs that refuse to quit, renaming a large batch of files in seconds, or running jobs in the background while you do other work.

Get started with an easy-to-understand overview of the Terminal and its partner, the shell. Then dive into commands neatly arranged into two dozen categories, including directory operations, file comparisons, and network connections. Each command includes a concise description of its purpose and features.Log into your Mac from remote locationsSearch and modify files in powerful waysSchedule jobs for particular days and timesLet several people use one Mac at the same timeCompress and uncompress files in a variety of formatsView and manipulate Mac OS X processesCombine multiple commands to perform complex operationsDownload and install additional commands from the Internet

The bestselling Mac guide, updated for the latest Mac OS X and now in full color

Mac OS X Lion represents a new era in the Mac operating system. This friendly guide is fully updated for the latest Mac OS X and provides everything new Mac users and users upgrading to Mac OS X Lion need to know. A bestseller in previous editions, "Mac OS X Lion For Dummies" covers all the cool stuff and prepares you for the quirks. So whether it's your first Mac or just an OS upgrade, you'll learn to tame your Lion with the expert advice of Bob "Dr. Mac" LeVitus and Dummies.Covers using the Finder, customizing Lion, adding widgets to the Dashboard, organizing and managing files and folders, searching with Spotlight, and working with SpacesExplores browsing the web with Safari, using Apple Mail and iCal, connecting a printer, performing backups with Time Machine, troubleshooting, and setting up a networkWalks readers through the new features of Mac OS X Lion, including FaceTime, Photo Booth, Launchpad, Mission Control, Full-screen apps, and moreGets you up and running with iTunes, downloading fun apps from the Mac App Store, and staying entertained with videos, photos, and other multimedia

You'll make your Lion roar with the friendly advice in "Mac OS X Lion For Dummies."

Dive into Swift 4.x, the latest version of Apple's easy-to-use programming language for macOS, iOS, watchOS, and tvOS. With this practical guide, you'll quickly get up to speed on language basics and then use Swift to build three complete apps, all tightly linked together: an iOS note-taking app, its OSX counterpart that uses iCloud to sync data, and an app for the Apple Watch that makes the user's data available at a moment's notice. You'll learn not only how to write code in Swift, but also why Swift works the way that it does, and how to build upon its foundations. Then you'll explore Swift in the wider world, including open-source frameworks that your apps can use, how to use app extensions make your app play nice with other apps, and how to take Swift beyond Apple's domain with open-source Swift tools.

Quickly learn how to get the most out of the Visual Studio for Mac integrated development environment (IDE). Microsoft has invested heavily to deliver their very best development tools and platforms to other operating systems. Visual Studio for Mac is a powerful developer tool that reinforces Microsoft's "mobile-first", "cloud-first", and "any developer, any platform, any device" strategy. With the author's guided expertise and extensive code samples, you will understand how to leverage the most useful tools in Visual Studio for Mac, the code editor, and the powerful debugger. You also will appreciate the author's guidance on collaborating with other team members using integrated tooling for the Git source control engine. Whether you are a Mac developer interested in cross-platform development or a Windows developer using a Mac, Beginning Visual Studio for Mac will quickly get you up to speed! What You'll Learn Prepare, configure, and debug in the Mac development environment Create cross-platform mobile apps for Android, iOS, and Windows with Xamarin and C# in Visual Studio for Mac Build cross-platform Web applications with .NET Core using Visual Studio for Mac Customize your productive and collaborative development environment Who This Book Is For Software developers using a Mac computer who want to build mobile or web applications that run on multiple operating systems

Think from a framework design perspective and move beyond straightforward coding skills. You'll design an enterprise level test framework that is capable of supporting both TDD and BDD at the same time, using the latest open source tools and coding best practices. Taking a less-is-more approach, superfluous information is excised in favor of sleek and direct instruction and focused coding practices. Your framework will be built with Spring-Boot, Gradle, and Junit. And it will support HP QC integration, Allure (TDD, BDD), Extent (BDD), and customized Pdf reporting (TDD, BDD). Extensive utilities are provided, such as HP ALM integration, device management utilities, email reporting, pdf reporting, OCR utility, Log utility, and more! There's also a special chapter on internationalization/localization testing in multiple languages. After reading this book, you'll have full confidence in your ability to build new test automation frameworks for yourself. Though primarily written for software professionals who are in test automation, recent engineering graduates who have programming knowledge and want to prepare for a role in mobile test automation will also find what's taught here helpful. Test engineers and computer science graduates alike can use what they learn here to become absolute pros in test automation.What You'll Learn Design an enterprise level mobile test automation framework capable of supporting both TDD and BDD Work with the latest open source tools and coding best practices Build with Spring-Boot, Gradle, and Junit while supporting HP QC integration, Allure, Extent, and customized PDF reporting Who This Book Is For Software professionals working in test automation. Recent engineering graduates who have programming knowledge and want to prepare for a role in mobile test automation should also find it helpful.

Enterprise Mac Security is a definitive, expert-driven update of the popular, slash-dotted first edition which was written in part as a companion to the SANS Institute course for Mac OS X. It contains detailed Mac OS X security information, and walkthroughs on securing systems, including the new 10.11 operating system. A common misconception in the Mac community is that Mac's operating system is more secure than others. While this might be have been true in certain cases, security on the Mac has always still been a crucial issue. With the release of OS X 10.11, the operating system is taking large strides in getting even more secure. Even still, when sharing is enabled or remote control applications are installed, Mac OS X faces a variety of security threats, whether these have been exploited or not. This book caters to both the beginning home user and the seasoned security professional not accustomed to the Mac, establishing best practices for Mac OS X for a wide audience. The authors of this book are seasoned Mac and security professionals, having built many of the largest network infrastructures for Apple and spoken at both DEFCON and Black Hat on OS X security. What You Will Learn The newest security techniques on Mac OS X from the best and brightest Security details of Mac OS X for the desktop and server, and how to secure these systems The details of Mac forensics and Mac hacking How to tackle Apple wireless security Who This Book Is For This book is for new users, switchers, power users, and administrators that need to make sure their Mac systems are secure.

Interested in iPhone and iPad apps development? Want to learn more? Whether you're a self-taught iPhone and iPad apps development genius or have just made your way through the pages of Beginning iOS 7 Development, we have the perfect book for you. More iOS 7 Development: Further Explorations of the iOS SDK digs deeper into Apple's latest iOS 7 SDK. Bestselling authors Dave Mark, Alex Horovitz, Kevin Kim and Jeff LaMarche explain concepts as only they can-covering topics like Core Data, peer-to-peer networking using GameKit and network streams, working with data from the web, MapKit, in-application e-mail, and more. All the concepts and APIs are clearly presented with code snippets you can customize and use, as you like, in your own apps. If you are going to write a professional iPhone or iPad app, you'll want to get your arms around Core Data, and there's no better place to do so than in the pages of this book. The book continues right where Beginning iOS 7 Development leaves off, with a series of chapters devoted to Core Data, the standard for Apple persistence.Dave, Alex, Kevin and Jeff carefully step through each Core Data concept and show techniques and tips specifically for writing larger apps-offering a breadth of coverage you won't find anywhere else. The Core Data coverage alone is worth the price of admission. But there's so much more More iOS 7 Development covers a variety of networking mechanisms, from GameKit's relatively simple BlueTooth peer-to-peer model, to the addition of Bonjour discovery and network streams, through the complexity of accessing files via the web. Dave, Alex, Kevin, and Jeff will also take you through coverage of concurrent programming and some advanced techniques for debugging your applications. The enhanced multitasking, threading, memory management and more are important. Apps are getting more and more complex, including sophisticated game apps that offer virtual or augmented reality experiences and new mapping views that take advantage of sensors and other APIs in the newest iOS 7 SDK. Whether you are a relative newcomer to iPhone and iPad or iOS development or an old hand looking to expand your horizons, there's something for everyone in More iOS 7 Development.What you'll learn * How to build apps customized for the iPad, the world's most popular tablet * How to utilize a variety of networking mechanisms, including peer-to-peer connections over Bluetooth using GameKit * Details on the addition of Bonjour discovery and network streams * How to embed maps with Map Kit and use in-application email How to access a user's iPod library and integrate music into apps * Essentials of concurrent programming and advanced debugging techniques * How to work with enhanced multitasking, threading, memory management and other APIs Tips on working with data from the web and the cloud, including Apple's iCloud * How to deal with Core Data: key concepts and techniques for writing larger applications * How to work with the iOS SDK when dealing with sensors, gyroscopes, etc. for augmented reality experiences in game and socia media appsWho this book is for This book serves as a complimentary book to Beginning iOS 7 Development and is suitable for those aspiring app developers new to iPad app development. Prior Objective-C programming experience would be helpful, but not required.

Interested in iPhone and iPad apps development? Want to learn more? Whether you are a relative newcomer to iPhone and iPad or iOS development or an old hand looking to expand your horizons, we have the perfect Swift-flavored book for you. The update to the bestselling More iPhone Development by Dave Mark and Jeff LaMarche, More iPhone Development with Swift digs deeper into the new Apple Swift programming language and iOS 8 SDK, explaining complex concepts and techniques in the same friendly, easy-to-follow style you've come to expect. More iPhone Development with Swift covers topics like Swift, Core Data, peer-to-peer networking using Multipeer Connectivity, working with data from the web, MapKit, in-application e-mail, Camera Live-Previews integration, Barcode scanning, Face recognition and more. All the concepts and APIs are clearly presented with code snippets you can customize and use, as you like, in your own apps. You'll journey through coverage of concurrent programming and some advanced techniques for debugging your applications.

There's more to build than just game apps for the Apple iTunes App Store. There are rich media or multimedia apps, for example. You can build media or utility apps that take advantage of media such as sound, music, photos, video, animation and other graphics and combines them into a rich media experience or can just make your utility app come alive. Beginning iOS Media Apps Development is a ground-breaking tutorial that explores the near limitless, programmable audio-visual capabilities of the iPhone, iPad and iPod touch using 5 real-world examples or case study apps. This book includes detailed step-by-step instructions and important background information from one of the worlds' most successful media app developers out there, Michael Zaletel. What you'll learn How to build a rich, dynamic media or multimedia apps using iOS SDK Get your hands dirty right away with a flash light app, and later 4 other app case studies in remainder of this tutorial What are the fundamentals of iOS media How to do develop and integrate photos on iOS How to create, edit and build the audio experience into your apps that have sound and music How to create, edit and build the video and animation experience into your apps How to combine these experiences and much more Who this book is for This book is for iOS app developers with at least some experience with the iOS SDK, Objective-C and/or Cocoa touch.

Microsoft Office for iPad is here! So learn the tips, tricks, and get around the gotchas in Microsoft Office for iPad with Pro Office for iPad. This book shows you how you can become productive quickly by avoiding those annoyances and confusions and slow-me-downs that can happen when you start using Office with your fingers! How is Office for iPad different from Office on your Mac or PC? Which features do the Office for iPad apps have, which do they lack, and how can you work around their limitations? How can you share your files among the different versions of Office? How quickly can you work without the physical keyboard and keyboard shortcuts you're used to -- and which keyboard shortcuts can you use if you connect a hardware keyboard to your iPad? Whether you plan to write a few letters or your dissertation, run your home office away from home, or use your iPad for daily business, Pro Office for iPad will show you how to get the most out of Word, Excel, and other Office apps on your iPad. Enjoy your new freedom and still be as productive as ever with the skills and techniques you'll learn in Pro Office for iPad.

The professional development team that brought you two editions of Objective-C for the Absolute Beginners and have taught thousands of developers around the world to write some of the most popular iPhone apps in their categories on the app store, have now leveraged their instruction for Swift. Swift for Absolute Beginners is perfect for those with no programming background, those with some programming experience but no object-oriented experience, or those that have a great idea for an app but haven't programmed since school. Gary Bennett and Brad Lees are full-time professional iOS developers and have developed a broad spectrum of apps for Fortune 500 companies. The authors have taken their combined 12 years of writing apps, teaching online iOS courses, the experience from their first two iOS books, along with their free online instruction and free online forum to create an excellent training book. Topics include: How to be successful at learning Swift Using Swift Playgrounds to learn iOS development quickly What is Object Oriented Programming What are Swift classes, properties, and functions Proper user interface and user experience design Swift data types: integers, floats, strings, booleans How to use Swift data collections: arrays and dictionaries Boolean logic, comparing data, and flow control Writing iPhone apps from scratch Avoiding Swift pitfalls Many students have a difficult time believing they can learn to write iOS apps or just staying motivated through learning the process. This book, along with the free, live online training sessions, helps students stay motivated and overcome obstacles while they learn to be great iOS developers.

Pro iOS Continuous Integration teaches you how to utilize the strengths of continuous integration in your everyday work. CI is more popular now than ever, as iOS developers realize how time-consuming building and deploying an application for testing purposes and quality assurance can be. This book shows you how to make your developing life easier, with real-world applications and examples. With this book, you will learn what continuous integration and continuous delivery really are and how they can be used in your iOS projects. You will learn how to release an iOS application outside the App Store using Xcode. You'll understand how to leverage the power of the command line to build your projects, and run your tests. You'll use Jenkins and Bamboo to architect automatic builds and automate the whole build process. In addition, you'll also learn how to use Xcode server and bots, what quality assurance tools can be used to measure the quality of your code, and how to send builds to your beta testers. Author Romain Pouclet provides hands-on, practical experience in iOS continuous integration and, using this book, you will see that it's not actually that hard to set up a fully-featured continuous integration platform, whether you are an independent iOS developer working from home or a member of a team in a big company.

So you've got an idea for an iPhone app - along with everyone else on the planet. Set your app apart with elegant design, efficient usability, and a healthy dollop of personality. "Best iPhone App Design" takes you from concept to polished interface design with plain-spoken principles and a rich collection of visual examples for designing exceptional interfaces for the iPhone and iPod Touch. Witty, down-to-earth, and irreverent, this guide is for everyone involved in the app design process: designers, programmers, managers, and marketers. You'll discover practical advice for sharpening your app's features, creating an effortless user experience, using iPhone controls correctly, and creating your own personality-packed visuals. At every stage, you'll find a gallery of app screenshots to illustrate best practices and inspire you with innovative designs. Case studies let you look over the shoulders of the best app developers, following the evolution of app designs from early sketches to finished product. The book's common-sense principles will equip you to ask the right questions throughout the design process to make aesthetic, technical, and usability decisions that will make your app a pleasure to use.

You can set your watch to it: As soon as Apple comes out with another version of Mac OS X, David Pogue hits the streets with another meticulous Missing Manual to cover it with a wealth of detail. The new Mac OS X 10.4, better known as Tiger, is faster than its predecessors, but nothing's too fast for Pogue and "Mac OS X: The Missing Manual," There are many reasons why this is the most popular computer book of all time.

With its hallmark objectivity, the Tiger Edition thoroughly explores the latest features to grace the Mac OS. Which ones work well and which do not? What should you look for? This book tackles Spotlight, an enhanced search feature that helps you find anything on your computer; iChat AV for videoconferencing; Automator for automating repetitive, manual or batch tasks; and the hundreds of smaller tweaks and changes, good and bad, that Apple's marketing never bothers to mention.

"Mac OS X: The Missing Manual, Tiger Edition" is the authoritative book that's ideal for every user, including people coming to the Mac for the first time. Our guide offers an ideal introduction that demystifies the Dock, the unfamiliar Mac OS X folder structure, and the entirely new Mail application. There are also mini-manuals on iLife applications such as iMovie, iDVD, and iPhoto, those much-heralded digital media programs, and a tutorial for Safari, Mac's own web browser.

And plenty more: learn to configure Mac OS X using the System Preferences application, keep your Mac secure with FileVault, and learn about Tiger's enhanced Firewall capabilities. If you're so inclined, this Missing Manual also offers an easy introduction to the Terminal application for issuing basic Unix commands.

There's something new on practically every page, and David Pogue brings his celebrated wit and expertise to every one of them. Mac's brought a new cat to town and we have a great new way to tame it.

Updated and expanded for the new Apple iOS8, The Business of iOS App Development, Third Edition shows you how to incorporate marketing and business savvy into every aspect of the design and development process, giving your app the best possible chance of succeeding in the App Store. This book is written by experienced developers with business backgrounds, taking you step-by-step through cost-effective marketing techniques that have proven successful for professional iOS app creators-perfect for independent developers on shoestring budgets. No prior business knowledge is required. The phenomenal success of the iPhone, iPad and the iPod touch have ushered in a "gold rush" for developers, but with well over a million apps in the highly competitive App Store, it has become increasingly difficult for new apps to stand out in the crowd. Achieving consumer awareness and sales longevity for your iOS app requires a lot of organization and some strategic planning. This is the book you wish you had read before you launched your first app!

Managing Apple Devices, Third Edition will enable you to create an effective plan for deploying and maintaining groups of Apple devices using iOS 9 and OS X El Capitan in your organization. This all-in-one resource teaches a wide variety of Apple management technologies; explains the theory behind the tools; and provides practical, hand-on exercises to get you up and running with the tools. You will be introduced to Apple management technologies including Mobile Device Management, the Volume Purchase Program, and the Device Enrollment Program. For example, not only will you learn how to use Profile Manager-Apple's implementation of Mobile Device Management-but you will also learn about the ideas behind profile management and how to make configuration easier for both administrators and users while maintaining a highly secure environment. The exercises contained within this guide are designed to let you explore and learn the tools provided by Apple for deploying and managing iOS 9 and OS X El Capitan systems. They start with verification of access to necessary services, move on to the configuration of those services, and finally test the results of those services on client devices. Each lesson builds on previous topics and is designed to give technical coordinators and system administrators the skills, tools, and knowledge to deploy and maintain Apple devices by: Providing knowledge of how Apple deployment technologies work Showing how to use specific deployment tools Explaining deployment procedures and best practices Offering practical exercises step-by-step solutions available

Think your Mac is powerful now? This practical guide shows you how to get much more from your system by tapping into Unix, the robust operating system concealed beneath OS X's beautiful user interface. OS X puts more than a thousand Unix commands at your fingertips-for finding and managing files, remotely accessing your Mac from other computers, and using freely downloadable open source applications. If you're an experienced Mac user, this updated edition teaches you all the basic commands you need to get started with Unix. You'll soon learn how to gain real control over your system. Get your Mac to do exactly what you want, when you want Make changes to your Mac's filesystem and directories Use Unix's find, locate, and grep commands to locate files containing specific information Create unique "super commands" to perform tasks that you specify Run multiple Unix programs and processes at the same time Access remote servers and interact with remote filesystems Install the X Window system and learn the best X11 applications Take advantage of command-line features that let you shorten repetitive tasks

With Sierra, Apple brings never-before-seen features to macOS-like Siri voice control, file sharing across all your iOS devices, picture-in-picture mode for iTunes and Safari, and AI photo search. Once again, David Pogue brings his humor and expertise to the #1 bestselling Mac book. Whether you're a developer or a home-user, this guide offers a wealth of detail on Apple's OS X 10.12 operating system, this new edition covers everything Sierra has to offer. Perfect for newcomers. Get crystal-clear, jargon-free introduction to the Dock, the macOS folder structure, Safari, Mail, and iCloud. Go in-depth. Learn how to use key new features such as Optimized Storage, the Universal Clipboard, Siri for Mac, and iCloud Drive Sync. Get the full story. David Pogue doesn't stop at telling you how to use macOS features. He wants you to know why to use them-and how to avoid common pitfalls.