This volume covers most of the courses and some of the seminars that were given at the 1969 Varenna summer school on relativity and cosmology. They should prove useful in bridging the gap between the standard textbooks and the flood of research articles on these topics.
Ehler's article is an extensive, essentially self-contained introduction both to general relativity and to general-relativistic kinetic theory. It is followed by Geroch's article on some of the global implications of the theory. The two articles following, by Ellis and Sciama, are complementary. Together they constitute a detailed review of cosmology. The last main lecture series, by Thorne, covers many aspects of the currently hot subject, relativistic stellar structure. The remaining articles cover some of the seminars presented at the summer school.