Target audience: testers, developers, project managers, Agile coaches
Urs’ comment: This book is a great introduction to ATDD and provides very good guidance and examples. Its 212 pages are read well and quickly. So if you are new to ATDD, you should read this book. If you are already familiar with ATDD and specifying by example, the third part provides some more in detail stuff like team collaboration and refactoring of tests. The only thing I miss is a wider look at approaches to ATDD than the ones presented: Cucumber and Fitness. See here for another, more developer-centric approach providing better refactoring possibilities.