The present report covers the period 1976–1978. As with previous reports it has not been possible to write an all- inclusive account covering everything published, or even every field under investigation; the number of contributions to extragalactic research is increasing enormously fast. Summaries of the papers may be found in the Astronomy and Astrophysics Abstracts.

The report is divided into ten sections, including the four Working Groups, and they have been prepared by the Vice-President, by members of the Organizing Committee and by the Chairmen of the Working Groups.