Wide and fascinating is the field of research on tryptophan, a most versatile amino acid, transformed, as it is, in our organism into many biologically active substances. This volume contains the proceedings of the Eighth International Meeting on Tryptophan Research, held at the University of Padova, Padova, Italy, from June 25 to 29 1995, under the auspices of the University of Padova, National Research Council, Italian Chemical Society-Division of Pharmaceutical Sciences, Region ofthe Veneto and City of Padova. The meeting was held in Padova to commemorate Prof. Luigi Musajo twenty years after his death and the editors dedicate this book to him in recognition of his pioneering work in tryptophan metabolism. Prof. Osamu Hayaishi delivered the Musajo Memorial Award Lecture: Tryptophan oxygenase. and sleep. Figure I shows the ISTRY President Prof. Simon N. Young presenting the Musajo Memorial Medal to Prof. Hayaishi during the Opening Ceremony. Two hundred scientists from twenty two countries participated in the meeting. These proceedings contain 121 papers encompassing a variety of topics and disciplines.