Book excerpt: In the interstellar medium - which occupies the space between the stars in galaxies - new stars are born from material that is replenished by the debris ejected by stars when they die. This book presents a detailed account of the atomic and molecular processes that give rise to the radiation we observe from the interstellar medium, knowledge that is essential to understanding star formation in our own and other galaxies. This Second Edition has been thoroughly updated and extended to cover related topics in radiation theory. It considers the chemistry of the interstellar medium, both in the present epoch and the early Universe. The book discusses the physics and chemistry of shock waves, which are produced by the jets of matter generated as a consequence of star formation. The methods for calculating rates of collisional excitation of interstellar molecules and atoms are explained, with emphasis on the quantum mechanical method. A comprehensive manual for studying collisional and radiative processes in the interstellar medium, this book will be ideal for researchers involved in calculating the rates of such processes, for those studying the interstellar medium and star formation, as well as for physical chemists specializing in collision theory or in the measurement of the rates of collision processes. Book jacket.