This is an introductory textbook on isometry groups of the hyperbolic plane. Interest in such groups dates back more than 120 years. Examples appear in number theory (modular groups and triangle groups), the theory of elliptic functions, and the theory of linear differential equations in the complex domain (giving rise to the alternative name Fuchsian groups). The current book is based on what became known as the famous Fenchel-Nielsen manuscript. Jakob Nielsen (1890-1959) started this project well before World War II, and his interest arose through his deep investigations on the topology of Riemann surfaces and from the fact that the fundamental group of a surface of genus greater than one is represented by such a discontinuous group. Werner Fenchel (1905-1988) joined the project later and overtook much of the preparation of the manuscript. The present book is special because of its very complete treatment of groups containing reversions and because it avoids the use of matrices to represent Moebius maps. This text is intended for students and researchers in the many areas of mathematics that involve the use of discontinuous groups.

Increasing technological sophistication in many countries and the resulting larger world trade has indicated a need to pay greater attention to the international aspects of user interfaces. Many American companies are approaching a situation where half of their sales are outside the United States, and companies in smaller countries often have a much larger proportion of their sales outside their own country. This means that software sales will increasingly depend on their international usability and not just their domestic usability. Seen from a user's perspective more than half of the world's software users will be using interfaces which were originally designed in a foreign country. Usability for this large market of users will depend upon increased awareness of the issues involved in designing user interfaces for international use.
As the European community aims to establish the so-called Single Market by the end of 1992, international software will become even more important in that part of the world. And as if it wasn't hard enough to design user interfaces for use in Europe, there are a further set of problems connected with user interfaces for Asia. Both of these issues are examined in depth.
This is the first publication of its kind to appear on the topic of international user interfaces, and presents both general guidelines and a number of detailed case studies on the many aspects entailed. The book will be of considerable interest to project managers, lecturers, students, developers of basic software and user interface designers.

Written by the author of the best-selling HyperText & HyperMedia, this book is an excellent guide to the methods of usability engineering. The book provides the tools needed to avoid usability surprises and improve product quality. Step-by-step information on which method to use at various stages during the development lifecycle are included, along with detailed information on how to run a usability test and the unique issues relating to international usability.
* Emphasizes cost-effective methods that developers can implement immediately
* Instructs readers about which methods to use when, throughout the development lifecycle, which ultimately helps in cost-benefit analysis.
* Shows readers how to avoid the four most frequently listed reasons for delay in software projects.
* Includes detailed information on how to run a usability test.
* Covers unique issues of international usability.
* Features an extensive bibliography allowing readers to find additional information.
* Written by an internationally renowned expert in the field and the author of the best-selling HyperText & HyperMedia.

Die Informationstechnologie im Zeitalter nach Gutenberg bedeutet neue Herausforderungen fur Autoren, Journalisten und Medienschaffende jeglicher Provenienz. Das Buch vermittelt praxisnah und beispielorientiert das grundlegende Wissen, wie Artikel, Bucher, Zeitschriften online oder offline konzipiert und realisiert werden. Dabei wird insbesondere gezeigt, wie im Internet selbst Moglichkeiten der Unterstutzung bei der Realisierung genutzt werden konnen.
Die Starke des Buches liegt vor allem da, wo sich die Darstellung an die Vermittlung des Wesentlichen halt und nicht bei den Zufalligkeiten konkreter Autorensysteme haften bleibt. Das Buch bleibt auf seine Weise aktuell und grundlegend gleichermassen.
Rezension in "Die Zeit im Buch" 51.Jg., 1/97, S. 15 1997
(...) Kein Ratgeber, sondern ein serioses, umfangreiches Buch mit vielen ung gut recherierten Hintergrundinformationen, (...)"

In the years since Jakob Nielsen's classic collection on interface consistency first appeared, much has changed, and much has stayed the same. On the one hand, there's been exponential growth in the opportunities for following or disregarding the principles of interface consistency-more computers, more applications, more users, and of course the vast expanse of the Web. On the other, there are the principles themselves, as persistent and as valuable as ever.

In these contributed chapters, you'll find details on many methods for seeking and enforcing consistency, along with bottom-line analyses of its benefits and some warnings about its possible dangers. Most of what you'll learn applies equally to hardware and software development, and all of it holds real benefits for both your organization and your users.
* Begins with a new preface by the collection's distinguished editor.
* Details a variety of methods for attaining interface consistency, including central control, user definitions, exemplary applications, shared code, and model analysis.
* Presents a cost-benefits analysis of organizational efforts to promote and achieve consistency.
* Examines and appraises the dimensions of consistency-consistency within an application, across a family of applications, and beyond.
* Makes the case for some unexpected benefits of interface consistency while helping you avoid the risks it can sometimes entail.
* Considers the consistency of interface elements other than screen design.
* Includes case studies of major corporations that have instituted programs to ensure the consistency of their products.