Interstellar matter is one of the most active fields of research in present-day astronomy. Observational information spans the full electromagnetic spectrum from gamma rays through rocket-ultraviolet, optical, infrared and millimeter to long radio waves. Results of research in physical chemistry find as much application as mathematical methods. Interstellar matter plays a leading role in studies of our Galaxy and of external galaxies, and contributes increasingly to stellar astronomy. At the 16th General Assembly of the International Astronomical Union, held in August 1976 in Grenoble, France, the many new developments in this vast field were surveyed in a number of sessions of Commission 34 (Interstellar Matter), mostly jointly with other Commissions of the Union. Separate sessions were devoted to: The hot interstellar gas phase, Interaction of stars and interstellar medium, Interstellar molecules and dust, The large-scale distribution of interstellar matter in the Galaxy, and Interstellar matter in external galaxies. Twenty-four invited review papers were presented and discussed in these sessions. The quality and success of these topical reviews made it seem desirable to make them available to a wider audience. Professor Edith Muller, the new General Secretary of the IAU, enthusiastically supported the idea. Most importantly, the reviewers - who had originally been pro mised that an oral paper was the only requirement - agreed to prepare written versions. I am grateful to Mrs. Muller, to the authors, and to Reidel Publishing for their collaboration in the preparation of this book.

IAU Symposium Number 52 on Interstellar Dust and Related Topics was held at Albany, N.Y., on the campus of the State University of New York at Albany from May 29 to June 2, 1972. The members of the Organizing Committee were: Dr A. D. Code, University of Wisconsin, Madison, Wis., U.S.A. Dr B. D. Donn, Goddard Space Flight Center, Greenbelt, Md., U.S.A. Dr A. Elvius, Stockholm Observatory, Saltsjobaden, Sweden. Dr T. Gehrels, Lunar and Planetary Laboratory, University of Arizona, Tucson, Ariz., U.S.A. Dr J. M. Greenberg (Chairman), State University of New York at Albany, Albany, N.Y., U.S.A. Dr H. C. van de Hulst, Sterrewacht, Leiden, Holland. Dr S. B. Pikel'ner, Sternberg Astronomical Institute, Moscow, U.S.S.R. Dr E. E. Salpeter, Cornell University, Ithaca, N.Y., U.S.A. Dr B. E. Turner, National Radio Astronomy Observatory, Charlottesville, Va., U.S.A. The suggestion was first made in 1971 that a symposium on interstellar grains would be timely. The response to the first preliminary announcement, which was sent out on November 29, 1971, was well beyond our expectations. The meeting was locally sponsored by the State University and by Dudley Observatory. The National Aeronautics and Space Administration and the National Science Foundation con tributed along with the IAU. There were 158 participants of whom 49 were from 15 countries outside the United States. A total of 92 papers were presented.

This is a comprehensive and richly illustrated textbook on the astrophysics of the interstellar and intergalactic medium--the gas and dust, as well as the electromagnetic radiation, cosmic rays, and magnetic and gravitational fields, present between the stars in a galaxy and also between galaxies themselves. Topics include radiative processes across the electromagnetic spectrum; radiative transfer; ionization; heating and cooling; astrochemistry; interstellar dust; fluid dynamics, including ionization fronts and shock waves; cosmic rays; distribution and evolution of the interstellar medium; and star formation. While it is assumed that the reader has a background in undergraduate-level physics, including some prior exposure to atomic and molecular physics, statistical mechanics, and electromagnetism, the first six chapters of the book include a review of the basic physics that is used in later chapters. This graduate-level textbook includes references for further reading, and serves as an invaluable resource for working astrophysicists. Essential textbook on the physics of the interstellar and intergalactic medium Based on a course taught by the author for more than twenty years at Princeton University Covers radiative processes, fluid dynamics, cosmic rays, astrochemistry, interstellar dust, and more Discusses the physical state and distribution of the ionized, atomic, and molecular phases of the interstellar medium Reviews diagnostics using emission and absorption lines Features color illustrations and detailed reference materials in appendices Instructor's manual with problems and solutions (available only to teachers)

The idea for an international symposium on the interstellar medium was first discussed at the University of Wyoming during the summer of 1984. It was obvious that the outstanding natural beauty of the Teton mountain range in northwestern Wyoming must be matched by a meeting with the broadest appeal to the astronomical community. If the meeting was to produce a book, it must likewise be an important contribution to the astronomical literature. It was for these reasons that early in the discussions, it was decided that the University should host a "school". with the invited speakers presenting tutorials on a broad range of topics involving the interstellar medium. The symposium proceedings would then be a compilation of the written versions of these presentations. It has been nearly a decade since Lyman Spitzer published his classic text on the interstellar medium and we felt the need for a school and book that would focus on the recent developments in our understanding of the inter stellar medium. Thus, we view this two-volume set as an adjunct text to Spitzer's book.

The gas and dust between the stars emit across the electromagnetic spectrum and are found in a range of physical conditions from diffuse plasmas to cold, dense molecules. Through their study we see how quantum processes shape the structure of our Galaxy and fluid mechanics sets the stellar mass scale. The Interstellar Medium is a very broad subject with layers of complexity, a long history and a steady flow of new results. This comprehensive yet accessible textbook provides a self-contained one-semester course for advanced undergraduate or beginning graduate students. It is written in a style that students can follow by themselves and allows instructors to use class time to go deeper into the details or show applications to current research. It makes extensive use of publicly accessible data to illustrate specific points and to encourage students to learn by performing their own analyses.

International Series of Monographs in Natural Philosophy, Volume 3, Interstellar Gas Dynamics focuses on the progress on research on the motion of gases in interstellar space and stellar atmospheres, including issues on cosmical gas dynamics and magnetohydrodynamics. The publication first offers information on the distribution, motion, and physical state of the interstellar gas. Topics include composition of the interstellar medium; cloud structure of the interstellar gas; spiral structure and distribution of the interstellar gas; ionization of the interstellar hydrogen; temperature of the interstellar gas; interaction between the interstellar gas and magnetic fields; and relativistic particles in an interstellar space. The book also takes a look at the discontinuities in the motion of the interstellar gas, as well as the fundamental theory of shock waves, ionization fronts, shock waves with light emission, and hydromagnetic discontinuities. The manuscript examines the equations of motion of the interstellar gas, including hydromagnetic equations of motion, one-dimensional motions and similarity solutions, motion of ionization fronts, and interstellar turbulence. The publication is a dependable reference for readers interested in interstellar gas dynamics.