If you want to support your agile activities with deep thinking and process guidance, I suggest you start at the top and work your way down this list.
I added the third category because good agile practices and software craftsmanship go hand in hand. Please read the craftsmanship books as soon as you can if you are writing code or supporting / managing those that do.
Finally, I am Microsoft leaning in my career, if you aren't, you can skip the TFS/Visual Studio centric titles.
Scrum and Agile
First Read this: Scrum Guide: Seriously, it all starts here.
Theory and Practice
|The Art of Unit testing|
|The Pragmatic Programmer|
|Working Effectively With Legacy Code|
|Agile Principles, Practices and Patterns in C#|