Use cases are a simple, straightforward -- yet very powerful -- way to express the functional requirements (or behaviors) of a system. Use cases have gained widespread acceptance because they make requirements less ambiguous by specifying exactly when and under what conditions certain behaviors occur. As a result, those who effective employ use cases to model their systems can better deliver projects on time, within budget, and with fewer defects. However, use case modeling is not that easy; it is a practice that comes with characteristics that can impact a project. In this new book, the authors allow you to benefit from their considerable experience making use cases work well in a number of different environments. With the advice, tips, and tricks presented herein, the reader will be further along the path to understanding and exploiting the power of use cases, and ultimately constructing better applications. In writing this book, the authors have worked closely with use case founder Ivar Jacobson, and the book is unique in that it presents a Rational Software Corporation-centric examination of this topic.