The present set of chapters by members of the staff of the National
Radio Astronomy Observatory deals with the basic fields of research
concerned with radio astronomy outside the solar system. The emphasis in
this volume is on the type of data available and its interpretation.
Basic theory is considered only where absolutely necessary, and little
discussion of receivers or techniques is entered into in most of the
chapters. The book is intended to take over where most textbooks on
radio astronomy leave off, that is, in the discussion of what is
actually known from the research done. In addition there is a chapter on
the technical aspects of inter- ferometry and aperture synthesis, since
so much of modern radio astronomy depends, and will depend in an ever
increasing manner, on such tools. The editors want to stress that the
chapters were not necessarily expected to be compre- hensive reviews of
any of the fields being covered, but rather, overall outlines which the
in- dividual authors felt would be suitable for graduate students and
interested workers in other fields. As a result, the lists of references
are not complete. This only reflects the preferences of the individual
authors and not the relative merit of those references included or
omitted.