Use cases are a way of defining system requirements by describing all the ways (cases) that the system can be used by all of its different clients. By taking the users’ view, thisapproach intends to make it easy for users to have direct inputinto system requirements. Use cases are even becoming standardized, as they have been incorporated into the industry-standard Unified Modeling Language (UML). The notation and semantics of use cases are illustrated in this introductory book. The approach is to show by example, and the authors limit their use of UML to what is needed to describe use cases. As an introduction, the book meets its goal, and it may be sufficient for managers or others who will read or contribute to use case–based requirement documents. Serious developers and others writing the use cases and the documents are likely to want a more complete, definitive description of use cases and their UML representation.

The description of use cases is illustrated with a single comprehensive example: a project to build an online order processing system for a mail-order company. This is an excellent approach, although the style used to present the development of the example system--as a series of conversations over dinner by the group of friends starting the company that will use thesystem--struck me as trite and inefficient. Other readers may find its informality and conversational style more appealing.

The book’s ten chapters move quickly from getting started to describing the intended system and using the elucidation of use cases to help define and refine the system, its requirements, and its design and architecture. The authors show how thevarious use case components grow and change throughout this process. This discussion culminates in a chapter that shows the complete use case description of the system. One weakness in the presentation is that there is never an example of something going wrong, so readers may get an unrealistic view of the ease of development with use cases.

The authors mix in some limited and rather simplistic advice on project management. They also include a short but interesting section on using the number of use cases to come up with use case points, analogous to function points, which are then used to produce a work estimate. Though they show little data to calibrate or verify this method, managers or researchers in software work or cost estimation may find this approach intriguing.

There are no exercises or references. An appendix contains an eclectic list of two dozen books for further reading. Some sample use case documentation templates are provided in another appendix, with a pointer to online versions in several common formats. The subset of UML notation used in the book is summarized in a third appendix.

All in all, the authors provide a good, short taste of use cases, but it may not satisfy all readers.