Despite the interest in parallelism and parallel processing, there is a fundamental question that has remained largely unexplored, namely the question of how to design multiprograms (parallel programs) from their specification. This book proposes a method for the formal development of multiprograms with a minimum of formal prerequisites. It is derived from the Owicki/Gries theory and can be put to work for the formal development of multiprograms regardless of whether the algorithms used are distributed or not.