The APS accelerator complex consists of the 7-GeV, 1.1-km storage ring operating with a 100-mA electron beam; the full-energy booster synchrotron; the 400-MeV particle accumulator ring; the 400-MeV pulsed linac; and the S-band rf thermionic electron gun. The APS has the largest number of installed 352-MHz cw rf power systems in the U.S. and the second largest installation of pulsed S-band rf power. The storage ring alone has over 1400 magnet power supplies and over 400 beam position monitors.More than 50 insertion devices are installed, with 11 different designs present in order to meeting the varying needs of different scientific programs. For historical, technical, and performance-related reasons, many APS systems are in-house designs. Excellent technical design, best-practice engineering, a demanding quality-assurance program, and a stringent preventive maintenance policy have yielded a reliable accelerator operation with a level of x-ray availability that typically exceeds 97% of scheduled user hours. The accelerator system also continually undergoes improvement to keep the APS competitive with leading global x-ray sources and to meet the changing needs of scientific users. The division's organization reflects the specialization required to maintain and operate key accelerator systems. Groups within ASD are dedicated to accelerator physics and operation, beam diagnostics, rf systems, magnet power systems and magnetic devices.