This book is intended as an introduction to object-orientation for 2nd, 3rd and 4th year computer science and software engineering students or those actively involved in the software industry. John Hunt adopts a 'hands on' approach providing a thorough introduction to O-O as well as to the language itself - unlike other Smalltalk books currently available which tend to focus primarily on the language. Issues such as Smalltalk style, typical Smalltalk bugs and the way to develop a Smalltalk program are comprehensively covered, as is the testing of O-O systems. A number of chapters are devoted to design, including chapters on the Unified Modeling Language (UML), Object Modeling Technique (using the UML) and the recent Patterns work. The inclusion of such subjects is unique among language oriented books. Finally there is also a look at the future of object-orientation and Smalltalk.