  At a distance of 8 kpc only, the center of the Galaxy provides a unique
testbed for studies about the physics of the interstellar medium and star
formation in the nuclei of galaxies. Since it shares many properties of other,
more spectacular nuclei, a detailed investigation of the Galactic Center is a
necessary step to gain better understanding of the physical processes governing
galactic nuclei in general. We review the characteristics of the central
molecular cloud layer, the physical properties of these clouds, and their
interplay with the magnetic field.
