Over the past few years, all the major internet or enterprise applications are developed or migrated to Rich Internet Application to support all the features that are provided in the desktop applications. This helps organizations keep the end users happy and also improves application deployment and maintenance. qooxdoo is a stable, open source RIA framework. If you are waiting and watching for the right time to migrate your application to qooxdoo, this is the right time!This book explains in detail about the rich user interface development in qooxdoo. It explains various concepts of qooxdoo framework in an easy to grasp and organized way, making it simple even for a novice in qooxdoo and also increases the competency level of the developer who is already working in qooxdoo.This book helps developers understand the qooxdoo framework, setup the environment, and start the development of RIA using qooxdoo. You will learn the core programming techniques in qooxdoo, user interface development in qooxdoo, testing & debugging qooxdoo applications, internationalization of qooxdoo applications to multiple languages, customizing the look and feel of qooxdoo applications using Themes, Performance management, etc.In the course of the book, we develop a complete application which will help the developer to understand the concepts better and to put things together to see the step-by-step progress to complete an application. By the end, this book will get the developer accustomed to the widgets and API available in the qooxdoo framework, and will enable him to design, develop, debug, and test the RIA in qooxdoo.