This compact book helps application developers bridge the gap between the theory of the newly created Unified Software Development Process and the practical realities necessary to design and build a software system. The authors present the key ingredients of the Unified Process and demonstrate how the process was conceived to work with UML, emphasizing the application of Use Cases as a primary design tool. The book incorporates a wealth of practical experience showcased by four case studies -- a hospital information system, a video on demand system, a portfolio management system, and a vehicle navigation (IVHS) system.