From conception to birth is traditionally nine months. The first emails regarding the volume you now hold in your hands-or the bits you have downloaded onto your screen-are dated 11 June 2005. From conception to birth has taken over four years. Springer’s LNCS Transactions on Pattern Languages of Programming is dedicated, first and foremost, to promoting, promulgating, presenting, describing, critiquing, interrogating, and evaluating all aspects of the use of patterns in programming. In the 15 years or so since Gamma, Helm, Johnson, Vlissides’s Design Patterns became widely available, software patterns have become a highly effective means of improving the quality of programming, software engineering, system design, and development. Patterns capture the best practices of software design, making them available to everyone participating in the production of software. A key goal of the Transactions Series is to present material that is validated. Every contributed paper that appears in this volume has been reviewed by both patterns experts and domain experts, by researchers and practitioners. This reviewing process begins long before the paper is even submitted to Transactions. Every paper in the Series is first presented and critiqued at one of the Pattern Languages of Programming (PLoP) conferences held annually around the world. Prior to the conference, each submitted paper is assigned a shepherd who works with the authors to improve the paper. Based on several rounds of feedback, a paper may proceed to a writers’ workshop at the conference itself.