For several years I have been interested in advocating practical methods in general and Extreme Programming in particular. When I do this, people often question how it fits into my ongoing interest in design patterns. Indeed, I've heard people argue that by promoting refactoring and evolutionary design, I'm retracting what I've written about analysis and design patterns.However, a quick glance at people is enough to realize that this view is flawed. Look at prominent members of the Models community and prominent members of the agile and XP communities and you'll see a huge intersection. The truth is, patterns and evolutionary design have had a close relationship from the very beginning.Josh Kerievsky has been at the center of this overlap. I first met him when he was successful in New York and organized study groups. These groups collaborated on the growing literature on design patterns. I quickly learned that Josh's understanding of design patterns was unrivaled, and I gained a lot of insight into those patterns by listening to him. Josh was an early adopter of the remake and was an extremely helpful critic of my book. Therefore, it was no surprise to me that he was also the pioneer of Extreme Programming. His article on patterns and Extreme Programming from the first XP conference is one of my favourites.