This book is an outcome of the VIII International Sponge Workshop held at the Centre for Advanced Studies of Blanes (C.S.I.C.) in June 1992. Through a series of original research papers, this volume covers a wide scope of sponge subjects comprising traditional and new approaches to the systematics and biogeography, expert systems applied to classificatory tasks, relationships with microsymbionts, chemical defences, and other ecological topics dealing with sponges.