  The ATLAS muon spectrometer consists of several major components: Monitored
Drift Tubes (MDTs) for precision measurements in the bending plane of the
muons, supplemented by Cathode Strip Chambers (CSC) in the high eta region;
Resistive Plate Chambers (RPCs) and Thin Gap Chambers (TGCs) for trigger and
second coordinate measurement in the barrel and endcap regions, respectively;
an optical alignment system to track the relative positions of all chambers;
and, finally, the world's largest air-core magnetic toroid system. We will
describe the status and commissioning of the muon system with cosmic rays and
plans for commissioning with early beams.
