The reason for writing this book now is that the words and distinctions finally are correlating with descriptions of project life and project results. They are proving more valuable for diagnosis and intervention than any of the tools that I used previously.

The ideas in this book have been through dozens of development teams, eight methodology designs, and a number of successful projects on which I participated.

Agility

I am not the only person who is using these ideas:

· Kent Beck and Ward Cunningham worked through the late 1980s on what became called Extreme Programming (XP) in the late 1990s.

· Jim Highsmith studied the language and business use of complex adaptive systems in the mid-1990s and wrote about the application of that language to software development in his Adaptive Software Development.

· Ken Schwaber and Jeff Sutherland were constructing the Scrum method of development at about the same time, and many project leaders made similar attempts to describe similar ideas through the same years. When a group of us met in February 2001 to discuss our differences and similarities, we found we had a surprising number of things in common. We selected the word agile to describe our intent and wrote the Manifesto for Agile Software Development (Appendix A).

We are still formulating the principles that we share and are finding many other people who could have been at that meeting if they had known about it or if their calendars had permitted their presence.

Core to agile software development is the use of light-but-sufficient rules of project behavior and the use of human- and communication-oriented rules.

Agility implies maneuverability, a characteristic that is more important now than ever. Deploying software to the Web has intensified software competition further than before. Staying in business involves not only getting software out and reducing defects but tracking continually moving user and marketplace demands. Winning in business increasingly involves winning at the software-development game. Winning at the game depends on understanding the game being played.