The sixth Taniguchi Symposium on the Theory of Condensed Matter was held between 14-18 November 1983 at Kashikojima. Japan. During the Symposium, about twenty participants lived together and discussed the magnetic super conductors and related problems in an active and friendly atmosphere. This volume contains the papers presented at this Symposium. A strong impetus for organizing a Symposium of this subject is afforded by recent intense interest and accumulated information on magnetic and other novel superconductors newly discovered, and indeed the Symposium has pro duced many excellent...