This book has two audiences: the practising Requirements Engineer and the advanced student of software engineering or computer science. The book is unique because it introduces latest research results and, at the same time, presents highly practical and useful techniques. This book is complementary to texts on software requirements and system Requirements Engineering because of its focus on the problems caused by the fact that Requirements Engineering involves people. Throughout this book the author has sought to introduce the reader to a number of techniques which have not previously been included within mainstream computer science literature. The techniques chosen have been shown to work in practice in both commercial and research pro­ jects. The appendices contain step-by-step guides to particular tech­ niques; sufficient detail is provided for readers to try the techniques for themselves. The problem faced by the Requirements Engineer is complex, it con­ cerns meeting the needs of the customer and at the same time meeting the needs of the designer.