Book excerpt: "It is well known that not only are design errors more frequent than coding errors in the production of software, but that they also take more time to be detected and corrected. It is the thesis of this book that a proper design methodology can produce programs of higher reliability and extensibility. The author presents an impressive set of guidelines and principles to aid in the design of medium- to large-sized programs, as well as examples that show proper application of the methodology. Most chapters in the book contain exercises that test the reader's understanding of the material presented, and a complete set of answers is provided at the end." -- Preface.