The CMS Muon System and Physics Performance

The CMS experiment will take data at the CERN LHC starting from 2007. The CMS muon system has been designed to identify, reconstruct and measure muons with high efficiency and accuracy. In this paper the layout of the system and the key features of the detectors are presented. The reconstruction algorithms, in the context of the High Level Trigger, and their performance in term of resolution, rate reduction and trigger efficiency are also discussed