This book is a guide to building a rich web application using Grails. The approach taken for building the application is incremental and iterative; each chapter will produce a working addition to the application, or iterate over existing features, as well as introduce and carefully explain the new part of the Grails framework used. The book does not go into exhaustive descriptions of every detail of Grails. While there is a lot of code in the book, there are very few large code listings. As you will find, it is not necessary to write reams of code to get results using Groovy and Grails. This book is aimed at Java web developers looking for ways to build web applications quickly, and wanting to find out how it's done quickly. If you are frustrated with integrating the many different frameworks that are available for web development and want to get on with building slick web applications for your users, then this book is for you. Grails is built on the Groovy language, but experience in Groovy is not required, as you will learn enough about Groovy to understand how to use Grails.