ZK is an open-source web development framework that enables web applications to have the rich user experiences and low development costs that desktop applications have had for years. ZK includes an Ajax-based event-driven engine, rich sets of XML User Interface Language (XUL) and XHTML components, and a markup language. The ZK rich client framework takes the so-called server-centric approach: the content synchronization of components and the event pipelining between clients and servers are automatically done by the engine and Ajax plumbing codes are completely transparent to web application developers. Therefore, the end users get rich user interfaces with similar engaged interactivity and responsiveness to that of desktop applications, while for programmers, development remains similar in simplicity to that of desktop applications. This book is a Developer's Guide that steps you through the ZK framework with examples. It starts with installing and configuring ZK and takes you on to integrate it with other frameworks. By the time you are through the book you will be able to build an application on your own.