Research on the complexity of Boolean Functions in non- uniform computation models is now one of the most interesting and important areas of research in theoretical computer science. It has a direct relevance to practical problems in the Computer Aided Design of digital circuits. In this book Professor Dr Wegener presents a large number of recent research results for the first time. Initially he deals with the well-known computation models (circuits and formulae), and he goes on to special types of circuits, parallel computers, and branching programs. Basic results are included as well as the most recent research results. The Complexity of Boolean Functions assumes a basic knowledge of computer science and mathematics. It deals with both efficient algorithms and lower bounds. At the end of each chapter there are exercises with varying levels of difficulty to help students using the book.