The Cologne-Bonn-Zermatt symposium is a well established series of conferences, occurring on a 5-year cycle, on the dense interstellar medium and related topics. The main results constitute valuable proceedings that offer everyone working in this field an authoritative and comprehensive source of reference.

Gas and Dust at High Redshifts.- Molecular Spectroscopy and Astrophysics.- Structure and Dynamics of the ISM in External Galaxies.- Structure and Dynamics of the ISM in the Milky Way.- Galactic Center.- New Observatories and Instrumentation.- Magnetic Fields in the ISM.- Physical Conditions and Processes in the ISM.- Astrochemistry.- Star Formation and Late Stages of Stellar Evolution.