Like a lot of terminology, “agile development” and “agile testing” mean different things to different people. In this chapter, we explain our view of agile, which reflects the Agile Manifesto and general principles and values shared by different agile methods. We want to share a common language with you, the reader, so we’ll go over some of our vocabulary. We compare and contrast agile development and testing with the more traditional phased approach. The “whole team” approach promoted by agile development is central to our attitude toward quality and testing, so we also talk about that here.