This book contains the refereed proceedings of the 12th International Conference on Agile Software Development, XP 2011, held in Madrid, Spain, in May 2011.The year 2011 marked the 10th anniversary of the Agile Manifesto. In this spirit, the XP conference continued its fine tradition of promoting agility by disseminating new research results in a timely manner and by bringing together researchers and practitioners for a fruitful mutual exchange of experiences. As introduced for XP 2010, there were again two different program committees, one for research papers and one for experience reports. Regarding the research papers, 11 out of 56 submissions were accepted as full papers; and as far as the experience reports were concerned, the respective number was 4 out of 17 submissions. In addition to these papers, this volume also includes the short research papers, the abstracts of the posters, the position papers of the PhD symposium, and the abstracts of the workshops.

Do you work on a team where not everyone is enthusiastic about good design and writing automated tests? How can you promote good practices? This handbook is a collection of concrete ideas for how you can get started with a Coding Dojo, where a group of programmers can focus on improving their practical coding skills. When you step into the Coding Dojo, you leave your daily programming environment, with all the associated complexities and problems, and enter a safe environment where you can try stuff out, make mistakes and learn with others. It's a fun and rewarding activity for any bunch of coders