There where not to much to discover inside of LINQ for me, but it could help a novice to understand the LINQ “magic” and use it efficiently.
Another very important point for me was the test driven approach. You could take this book as a guide for test driven design and development.
Reading this book chapter after chapter you will see how TDD helps you to come to a best API decision when working on a library. It demonstrates that on sometimes you should compromise functionality or performance to increase usability and maintain necessary level of protection.
Every chapter follows the same structure contains a lot of test and productive code, builds on top of the previous and makes a basement for the next one – remembers me the double linked list.
A must to read book for TDD + LINQ fans.