The four chapters in Part I tell you all you need to know to use the requirement patterns in Part II. Part I contains two chapters on requirements in general (on the how and the what, respectively) and two chapters on what requirement patterns themselves are all about.
This is a book about requirement patterns, so we don't want it to be bogged down by long explanations of how to specify requirements and what to include in a requirements specification. Yet you need at least a passing understanding of those subjects to make the most of the requirement patterns. How can we reconcile those goals? The answer is to provide longer, full versions of Chapters Chapter 1 and Chapter 12Ȅjust not in the printed book itself. They are available for download from the book's companion Web site, http://www.microsoft.com/mspress/companion/9780735623989. The Chapters Chapter 1 and Chapter 2 that follow are synopses of the full versions and are organized in the same way. They give you the quickest possible overview of these two subjects. If you want to know more about anything in one of the synopsis chapters, please refer to its full version.
Chapter 1 is a flying introduction to what requirements are all about and how to figure them out, whether you choose to do so in the traditional manner or take an agile approach. In this context, traditional means specifying all the requirements before designing and building the system; agile means worrying less about specification documents up front, and beginning development as early as possible.
Chapter 2 describes what a requirements specification needs to contain. The full version of Chapter 2 provides a level of guidance about the sections in a requirements specification that is similar to what the patterns provide for individual requirements. This enables you to write a complete, well-balanced, full requirements specification.
Chapter 3 describes the role that requirement patterns play, explains what each pattern contains (its anatomy), and introduces a few related concepts.
Chapter 4 discusses when and how to use requirement patterns, and describes how to produce new requirement patterns by tailoring existing patterns or by writing new ones from scratch.