This book provides an introduction to practical formal modelling techniques in the context of object-oriented system design. It is aimed at both practising software engineers with some prior experience of object-oriented design/programming and at intermediate or advanced students studying object-oriented design or modelling in a short course. The following features make this book particularly attractive to potential instructors: § The relationship with UML and object-oriented programming makes it easy to integrate with the mainstream computing curriculum. Although the book is about formal methods, it does not have to be treated as a specialist topic. § The use of tools and an accessible modelling language improves student motivation. § The industry-based examples and case studies add to the credibility of the approach. § The light touch approach means that the material appeals to students with a wider range of abilities than is the case in a conventional formal methods text. § Support materials as listed above.