Disclaimer: I served as a technical reviewer for several chapters of this book.
Understanding design patterns and how they are used in developing an application is a critical skill. It is important that developers be able to make use of the same lexicon when discussing application architecture. Books like "Design Patterns" by Eric Gamma, et al (affectionately referred to as the gang of Four, or GoF) do well to catalog design patterns and provide this lexicon but they are difficult to use as a guide to learning and understanding design patterns, especially for the less-experience developer. "Head First Design Patterns" provides the skills required to learn and understand what design patterns are and how to use them and does it in a fun, easy-to-read way.
Although this book does present many of the patterns found in the GoF book, it is not a design pattern catalog. Its real goal is to help the reader look at their applications in new ways to discover how design patterns can simplify their development efforts. Patterns are covered in great deal, some may say in almost too much detail, but the end result is a thorough understanding of the patterns under discussion as well as the whole reasoning behind using patterns in the first place.
Each pattern is discussed in a similar way. It generally starts with a programming problem that has been handed to the development team. They look at a typical, non-design pattern solution and point out the problems with this solution, usually involving issues with making future changes. The team then starts looking for alternate solutions and discovers a design pattern. The application is then refactored using the design pattern. Simplified UML diagrams and easy to follow Java programs are used throughout the book. All of this is done is an amusing way that will keep the reader interested and not distracted.
I can strongly recommend this book for any developer with a sense of humor who wishes to understand design patterns. Even if you are not a Java programmer, the programs are simple enough for any developer using an object oriented language to understand. The book does a great job of explaining object oriented design goals and showing how each pattern fits into those goals. You won't find a discussion of every design pattern known but you will find a highly instructive discussion of some of the most common patterns. Reading this book will provide you with the skills to understand design patterns and to understand why you should be using them.
This earned 5 stars on Amazon. The book is published by O'Reilly.
This review and all my other reviews can be seen on My Amazon Reviews page.