Just as architects and musicians need architectural drawings or music scores to be written using standard notations that everyone agrees on and understands, developers need a single, common, widely usable modeling language for the development of software systems. The UML has been proposed as this standard and has received the support of academic and industry heavyweights. The Unified Modeling Language User Guide is the first of three definitive UML works written by the creators of UML, Grady Booch, Jim Rumbaugh, and Ivar Jacobson. Together these three widely respected and world-famous methodologists form an unbeatable author team representing combined worldwide sales of their prior individual books of more than 250,000 copies. This book will introduce the core 80% of the UML, approaching it in a layered fashion and providing numerous examples of its application. The Unified Modeling Language User Guide is suitable for developers unfamiliar with UML or with modeling in general.