“Eric Evans has written a fantastic book on how you can make the design of your software match your mental model of the problem domain you are addressing. “His book is very compatible with XP. It is not about drawing pictures of a domain; it is about how you think of it, the language you use to talk about it, and how you organize your software to reflect your improving understanding of it. Eric thinks that learning about your problem domain is as likely to happen at the end of your project as at the beginning, and so refactoring is a big part of his technique. “The book is a fun read. Eric has lots of interesting stories, and he has a way with words. I see this book as essential reading for software developers—it is a future classic.”      —Ralph Johnson, author of Design Patterns “If you don’t think you are getting value from your investment in object-oriented programming, this book will tell you what you’ve forgotten to do.“Eric Evans convincingly argues for the importance of domain modeling as the central focus of development and provides a solid framework and set of techniques for accomplishing it. This is timeless wisdom, and will hold up long after the methodologies du jour have gone out of fashion.”      —Dave Collins, author of Designing Object-Oriented User Interfaces “Eric weaves real-world experience modeling—and building—business applications into a practical, useful book. Written from the perspective of a trusted practitioner, Eric’s descriptions of ubiquitous language, the benefits of sharing models with users, object life-cycle management, logical and physical application structuring, and the process and results of deep refactoring are major contributions to our field.”      —Luke Hohmann, author of Beyond