This introduction to molecular astrophysics gives an excellent up-to-date summary of the knowledge and outstanding questions in the field.This introduction to molecular astrophysics gives an excellent up-to-date summary of the knowledge and outstanding questions in the field. There are descriptions of the distributions and types of molecules observed in galactic and extragalactic sources, including those in the vicinity of active galactic nuclei, as well as a discussion of the chemistry of diffuse and dense clouds.This introduction to molecular astrophysics gives an excellent up-to-date summary of the knowledge and outstanding questions in the field. There are descriptions of the distributions and types of molecules observed in galactic and extragalactic sources, including those in the vicinity of active galactic nuclei, as well as a discussion of the chemistry of diffuse and dense clouds.This self-contained introduction to molecular astrophysics is an excellent summary of present knowledge and outstanding questions, one that will be valued by scientists who wish to become familiar with this field. The contributors describe the distributions and types of molecules observed in galactic and extragalactic sources, including those in the vicinity of diffuse and dense clouds. In addition, chemical reactions in shocks and dynamically evolving clouds are considered. This is a highly suitable text for astrophysicists, physical chemists, atomic and molecular physicists, atmospheric scientists, and students in advanced postgraduate courses on interstellar matter.Part I. Molecular Clouds and the Distribution of Molecules in the Milky Way and Other Galaxies: 1. Molecular clouds in the Milky Way P. Friberg and A. Hjalmarson; 2. Molecules in galaxies L. Blitz; Part II. Diffuse Molecular Clouds: 3. Diffuse cloud chemistry E. F. Van Dishoeck; 4. Observations of velocity and density structure in diffuse clouds W. D. Langer; 5. Shock chemistry in diffuse clouds T. W. Hartquist, D. ló›