M31, better known as the Andromeda Galaxy, is the nearest grand spiral galaxy. Its proximity allows us to reach high spatial resolutions and study it in great detail. Already early analysis of the polarized emission has shown that the turbulent and large-scale magnetic field is concentrated in a ring-like structure at 10 kpc radius. The presence of a regular field over such long distances can be explained by galactic dynamo theory. However, the structure of the M31's large-scale magnetic field is unusually simple. An almost purely axisymmetric field is not known from any other spiral galaxy. The aim of this work is to provide new clues to the understanding of M31's magnetic field structure, by utilizing new methods for data analysis, better resolutions and higher sensitivities than ever before, and by advancing into new wavelength regimes.

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 13 contains literature published in 1975 and received before August 15, 1975; some older literature which was received late and which is not recorded in earlier volumes is also included. We acknowledge with thanks contributions to this volume by Dr. J. Bouska, who surveyed journals and publications in the Czech language and supplied us with abstracts in English, and by the Common wealth Scientific and Industrial Research Organization (C.S.I.R.O.), Sydney, for providing titles and abstracts of papers on radio astronomy. We want to acknowledge valuable contributions to this vol ume by Zentralstelle ftir Atomkemenergie-Dokumentation, Leopoldshafen, which supported our ab stracting service by sending us retrospective literature searches.

A strong resurgence of interest in low-frequency radio astronomy in the past few decades has led to addressing many of the outstanding and challenging astrophysical and technical problems and issues. The GMRT has been in operation for close to a decade. Early results have been reported from LOFAR. The next generation of telescopes such as the LWA, MWA, MeerKAT, ASKAP and SKA should provide exciting challenges, results, and opportunities. To discuss recent results and astrophysical problems as well as a range of technical issues at low radio frequencies, a conference and workshop was held at the National Centre for Radio Astrophysics of the Tata Institute of Fundamental Research. This event commemorated the birth centenary of Dr. Homi J. Bhabha, who contributed immensely in both the sciences and the arts. There were approximately 130 participants from over a dozen countries. The conference brought together experts with a wide range of interests from major observatories and institutions across the world as well as younger research workers largely from within India. There were over 100 papers presented, including several extensive reviews, on a large variety of topics including low-frequency surveys and cosmology, extragalactic neutral hydrogen and OH, extragalactic radio sources, clusters of galaxies, our Galaxy, pulsars, transients and high-energy sources, Sun and planetary studies, and instrumentation and techniques. The book provides an overview of research at low radio frequencies and should be of interest to a wide spectrum of students and researchers.

While magnetic fields permeate the universe on all scales, the present book is dedicated to their investigation on the largest scales and affords a balanced account of both theoretical and observational aspects. Written as a set of advanced lectures and tutorial reviews that lead up to the forefront of research, this book offers both a modern source of reference for the experienced researchers as well as a high-level introductory text for postgraduate students and nonspecialist researchers working in related areas.

The study of extraterrestrial magnetic fields is a relatively new one, confirmation of the existance of the first such field (that of our Sun) having come a s late as 1908. In the past 30 years a great ammount of knowledge has been accumulated on Cosmic Magnetism, which has turned out to be a truly fascinating topic for study. Percy Seymour's book is the first to deal with the topic in a non-mathematical way, and he offers a fine introduction to his subject. The first three chapters consolidate our knowledge on magnetism in general and the magnetic field of the Earth, as well as discussing the reasons for studying astronomy and cosmic magnetism in particular. The remainder of the book is devoted to the main areas of cosmic magnetism - solar, plantetary and interplanetary fields, fields in stars and pulsars, fields of the milky way and fields in other galaxies. Cosmic Magnetism in an ideal book for sixth-formers and undergraduates studying physics or astronomy and will also appeal to amateur astronomers. as previous work on this topic has been 'hidden' in specialised academic journals.