Set Theory is both the most important and most difficult contribution to 20th century music analysis and composition of the last forty years. "Set Theory Objects" provides a comprehensive introduction to this theory and its practice, explaining the concepts and terminology used precisely and understandably. Computers are a valuable tool in set theoretic work. This book not only provides a survey of currently available software, it also describes the development of a new program for set theoretical applications. Particular attention is paid to the strategies followed in designing the program to make it a truly usable tool for musicians, regardless of their technical sophistication. Thus, this book is not only of interest to musicians, but can serve as a case study in human interface design.