This text is dedicated to the TUXEDO System release 6.1, used in such business systems as teller machine processing, library book requests, and petrol pump fulfilment. The work discusses the background architectural framework and motivation for the TUXEDO System, describes TUXEDO's features, and gives a tour through TUXEDO's development and administration facilities. Included are numerous examples of how the system can be used and answers to frequently asked questions. The authors have all worked on TUXEDO from its earliest days.