The following text forms the proceedings of a conference. It is supposed to contain what was actually reported and discussed, though it does this, one hopes, in a polished and organized way. A sense of actuality, a reporting quality, makes this book different from a collection of review papers as, for example, a book in the series on Stars and Stellar Systems. All Invited Reports have been included as the Reporters wrote them. The Editor's task has been restricted to improving the presentation, a process which in most cases involved only minor revisions. In a few Reports the Editor did some heavy rewriting; in those cases he checked with the Reporters. Obviously a different course had to be taken with respect to the Discussions. They were recorded on tape, transcribed verbatim and then passed back to the discussants. After the discussants returned their versions, the Editor rearranged and condensed the texts and made a considerable effort to provide references. (Unfortunately he was not able to locate all relevant Russian papers from 1968 and 1969. ) The Editor takes the responsibility for mistakes made in this process, which may have produced occasionally his own 'mix-master Universe'. Actually only a few discussion remarks were rejected, more often because of incomprehensibility, rather than because the remark was far from the subject of the Symposium, or was too long, or was too trivial. A few very long remarks have been condensed and put at the end of a Discussion.

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.

Gas dynamical effects govern the physics of many objects in the Universe ranging in scale from the intergalactic to the circumstellar. This book gives an up-to-date survey of the latest findings and theories from acknowledged experts in this particular field of astrophysics. Cosmical Gas Dynamics includes papers on the following subjects: -- shock waves caused by supernova explosions -- jets and maser sources -- the effects of gravitational fields on interstellar gas -- flow patterns determining where star formation will occur -- the remnant of the nova Rho Ophiuchi which exploded on 26 January 1985

Astronomy and Astrophysics Abstracts, which has appeared in semi-annual volumes since 1969, is de voted to the recording, summarizing and indexing of astronomical publications throughout the world. It is prepared under the auspices of the International Astronomical Union (according to a resolution adopted at the 14th General Assembly in 1970). Astronomy and Astrophysics Abstracts aims to present a comprehensive documentation of literature in all fields of astronomy and astrophysics. Every effort will be made to ensure that the average time interval between the date of receipt of the original literature and publication of the abstracts will not exceed eight months. This time interval is near to that achieved by monthly abstracting journals, com pared to which our system of accumulating abstracts for about six months offers the advantage of greater convenience for the user. Volume 18 contains literature published in 1976 and received before March 1, 1977; some older liter ature which was received late and which is not recorded in earlier volumes is also included.

This two-volume text is for new graduates on astronomy courses who need to get to grips with the physics involved in the subject. Four problem sets, averaging three problems per set, accompany each volume. The problems expand on the material covered in the texts and represent the level of calculational skill needed to write scientific papers in contemporary astrophysics.

The Encyclopaedia of Mathematics is the most up-to-date, authoritative and comprehensive English-language work of reference in mathematics which exists today. With over 7,000 articles from `A-integral' to `Zygmund Class of Functions', supplemented with a wealth of complementary information, and an index volume providing thorough cross-referencing of entries of related interest, the Encyclopaedia of Mathematics offers an immediate source of reference to mathematical definitions, concepts, explanations, surveys, examples, terminology and methods. The depth and breadth of content and the straightforward, careful presentation of the information, with the emphasis on accessibility, makes the Encyclopaedia of Mathematics an immensely useful tool for all mathematicians and other scientists who use, or are confronted by, mathematics in their work. The Enclyclopaedia of Mathematics provides, without doubt, a reference source of mathematical knowledge which is unsurpassed in value and usefulness. It can be highly recommended for use in libraries of universities, research institutes, colleges and even schools.