  The COMPASS Experiment at the CERN SPS has a broad physics program focused on
the nucleon spin structure and on hadron spectroscopy, using muon and hadron
beams. Main objectives for the spin program with the muon beam are the direct
measurement of the gluon contribution to the spin of the nucleon,
semi-inclusive measurements, and the measurement of the transverse spin
distribution $\Delta_T q$. The COMPASS apparatus consists of a two-stage large
acceptance spectrometer designed for high data rates and equipped with
high-resolution tracking, particle identification and electromagnetic and
hadronic calorimetry. The data taking is ongoing since 2002 and till now was
mainly devoted to the spin programme using a 160 GeV$/c$ naturally polarized,
$\mu^+$ beam and a polarized \mrf{^6LiD} target. First physics results from the
2002 and 2003 runs are presented.
