Muon identification and triggering with the ATLAS detector

Muons are a robust signature for interesting physics at LHC. ATLAS is building a high-resolution muon spectrometer, with stand-alone triggering and momentum-measurement capability over a wide range of transverse momentum, pseudo-rapidity and azimuthal angle. The muon spectrometer plays a crucial role in the ATLAS trigger system, which is organized as a multi-level architecture where the event selection is performed in three steps. This paper describes the Level-1 and Level-2 muon triggers with particular emphasis on b physics.