This is the first volume of a monumental work that is intended to give a complete treatment of reflecting telescope optics. It addresses the specialists in the field, both in the astronomical community and in industry. Consequently, subjects such as practical alignment, test techniques, and maintenance aspects occupy a significant part. Whereas the second volume will concentrate on technical aspects and modern developments, this book is devoted to the theory of reflecting telescope optics and with its historical development it should also be useful to students.