The third International Meeting on ‚Low Molecular Weight Sulfur Containing Natural Products,’sponsored by the International Union of Pure and Applied Chemistry, was held in the historical building of the Accademia Nazionale dei Lincei, Rome, Italy, June 18-21, 1979. The symposium was held in order to exchange knowledge in the intriguing and complex field of sulfur biochemistry. This theme brought together scientists from many speciali zed areas from organic and physical chemistry to biology and medicine. The interdisciplinary nature of the meeting gave to the participants the opportunity to discuss pro blems of common interest approached from different scienti fic standpoints. This volume contains 47 contributions presented at the meeting which mainly deal with new structural and metabolic aspects of sulfur biochemistry. An important aspect of such a scientific meeting is the rapid publication of the proceedings. Through the cooperation of the authors in providing ‚camera ready‘ copies of their manuscripts, the good efforts of the Orga nizing Committee, and the Plenum Press Publishing Co., it has been possible to publish this book within a few months of the meeting.