(This book introduces the main functions of the ESB (Enterprise Service Bus) as the core and infrastructure of SOA, and focuses on BEA's enterprise level ESB product, AquaLogic Service Bus (ALSB for short). In this book, readers will learn how ALSB connects with some traditional systems through many detailed examples, as well as the common design pattern of Web Services, to enrich their experience in SOA and ESB development and architecture. There are 15 chapters in this book, most of which are relatively independent in content, and readers can read each chapter separately. This book is readable and instructive for both novices who do not understand the concepts of ESB and SOA, and experts of ALSB.)