Agile Software Development Ecosystems by JimHighsmith, Addison Wesley 2002
This book basically brings together the major players and their methods, and explores the differences and similarities between them.
Included are discussions of:
Every new paradigm needs a clear, concise, yet thorough synthesis of the ideas surrounding it, and the personalities driving it. For AgileMethodologies, this is it. This book is highly underrated in my opinion. If you want to understand agile software development, there's only one book you need to read. That is a major accomplishment. Kudos to JimHighsmith.