This book focuses on conducting a comprehensive analysis of blockchain scalability serving large-scale application scenarios, from the “what, why, how� three perspectives, layer by layer. Gathering the latest state-of-the-art research advances in the area of key issues and technologies for blockchain scalability, it also presents some special and exciting insights on the existing and future blockchain scalability. Despite blockchain’s merits of decentralization, immutability, non-repudiation, and traceability, the current blockchain has faced a serious scalability bottleneck. The scalability bottleneck problem is mainly manifested in two aspects: low-performance efficiency and difficulty in functional extension. First, the security and reliability of the blockchain system come from the fact that most nodes of the whole network participate in a distributed consensus to maintain the ledger. The high-cost consensus mechanism makes limited performance of blockchain, and there is a big gap between the actual large-scale application system. In addition, in order to ensure the security of a single blockchain system, data between different blockchain systems are relatively isolated, making it difficult for assets and data to interact. This book explores the scalability of blockchain in depth, proposes meaningful approaches to the problems mentioned above, and builds an original theoretical system of blockchain scalability. It describes the root of blockchain scalability problems, mainstream blockchain performance, the classification of existing scalability problem solutions, and some exciting sharding-based approaches. It also includes open issues and future directions to scale blockchain for complex practical application scenarios. As such, this book will be a valuable resource for students, researchers, engineers, and policymakers working in various areas related to blockchain scalability, which is also of great significance for understanding and solving the bottleneck of blockchain scalability and realizing the practical large-scale commercial application of blockchain.

The Metaverse seamlessly integrates the real world with the virtual world and allows avatars to engage in a broad range of activities including entertainment, social networking, and trading. In this book, we dive into the Metaverse by discussing how blockchains connect various Metaverse components, digital currencies, and blockchain-empowered applications in the virtual world. On the other hand, Web3 has also attracted considerable attention due to its uniquely decentralized characteristics. The digital economy, currently undergoing a rapid development, is a critical driver to highly efficient societies. It is imperative that we investigate how to use Web3 technologies to address the critical concerns encountered during the development of the digital economy by fully exploring Web3. In this book, we also share insights into the Web3-based ecosystem in the Metaverse; topics of interest include decentralized finance, digital assets, the asset-trading market, etc.  Unlike most works on the subject, this book mainly concentrates on insights and discussions regarding blockchain, the Metaverse and Web3. In other words, it focuses on using blockchain technologies to enable an ecosystem for both the Metaverse and Web3. Topics addressed include blockchain fundamentals, smart contracts, value circulation in the Metaverse, the connection between the Metaverse and Web3, the establishment of the Metaverse on the basis of blockchain technologies, decentralized autonomous organization, decentralized storage, digital economy, Web3-based economic systems for the Metaverse, etc. This book will be a valuable resource for students, researchers, engineers, and policymakers working in various areas related to blockchain, the Metaverse and Web3. We hope that it will also inspire readers from academia and industry alike, and ultimately help them create a truly open, fair, and rational ecosystem for the Metaverse and Web3.