We released the first version of Composite Application Guidance in July 2008. The Composite Application Guidance for WPF is designed to help you more easily build enterprise-level Windows Presentation Foundation (WPF) client applications. This guidance will help you design and build flexible composite WPF client applications—composite applications use loosely coupled, independently evolvable pieces that work together in the overall application.
The Composite Application Guidance for WPF can help you develop your WPF client application in a modular fashion. With this approach, you manage the complexity of a large application by breaking it down into smaller, simpler modules. The module can evolve independently while working together as a unified application. The guidance includes a reference implementation, reusable library code (named the Composite Application Library), documentation, QuickStart tutorials, and hands-on labs.
Now you can read it in Japanese (http://msdn.microsoft.com/ja-jp/library/dd365013.aspx)
Composite Application Guidance for WPF は、エンタープライズ レベルの Windows Presentation Foundation (WPF) クライアント アプリケーションを容易にビルドできるようデザインされています。
Thanks goes to the folks in MSDN Japan.
Other relevant links
CodePlex site: http://www.codeplex.com/CompositeWPF
If you have used Composite UI Application Block (CAB) and are looking for guidance to move to Composite Application Library for WPF, you will find this document helpful. Composite Application Guidance for CAB Developers.pdf