The subject of this volume in the Astrophysics and Space Science Library is Electro- magnetic Radiation in Space. It is essentially based on the lectures given at the third ESRO Summer School which was held from 19 July to 13 August, 1965, in Alpbach, Austria. Fifty-eight selected students attended the courses representing the following countries: Austria (2), Belgium (1), Denmark (1), France (12), Germany (10), Italy (7), Netherlands (2), Spain (4), Sweden (6), Switzerland (3), United Kingdom (9), United States (1). Thirteen lectures courses and nine seminars were given by sixteen different...