Documentation
Books
The first Yii book is titled "Agile Web Application Development with Yii1.1 and PHP5".
It is an introductory book describing how to use Yii to develop a
real world project using the test-driven development (TDD) methodology.
Check this out if you want to quickly master Yii.
Second Yii book titled "Yii 1.1 Application Development Cookbook"
is a recipe book that contains 13 independent chapters full of useful
recipes covering most interesting Yii parts. If you are a developer
with a good knowledge of PHP5, are familiar with the basics of Yii,
and have tried to develop applications using Yii, then this book is
for you.
Visit the Book Website >
Tutorials
If you are new to Yii, you will likely want to start with these tutorials. They cover installation, fundamental concepts, and demonstrate how to build an entire database-driven Web application using Yii.
Class Reference
Once you are in the middle of developing a Yii application, you will become very familiar with the class reference. It contains the most accurate details about properties, methods and events of every class in the Yii framework.
Wiki Articles
Wiki articles are collaboratively written by Yii enthusiasts. You may find solutions to your specific Yii development tasks or problems among these articles.
Other Resources
In addition to the above documentation, there are several other resources contributed by active members in the Yii community that you may find useful.