The Tenth American Peptide Symposium was held on the campus of Wash ington University in St. Louis, Missouri, on May 23-28, 1987. More than 750 participants from around the world met to renew acquaintances, make new friends, and feast at the scientific explosion occurring in the field of peptide research. From over 85 oral presentations and 295 poster presentations, the manuscripts which make up this proceedings have been selected in order to present a synopsis of current research. In many ways, this meeting represented a culmination of forces clearly perceptible in the proceedings of previous meetings in which synthetic chemistry, spectroscopy, molecular biology, molecular modeling, and protein chemistry all are blended as needed to focus on interesting scientific problems. As peptides assume an ever increasingly important role in biological phenomena, our domain as peptide chemists has obviously expanded, and we are the richer for it. The session on conformation was highlighted by both predictions ofthree-dimensional structures of proteins (i. e., interleukin and human growth hormone) as well as determination of solution structures by 2D NMR. A growing interest in peptide mimetics stimulated much interest in reverse turn mimics, nonpeptide antagonists of peptide hormones, and amide bond isosteres. Increased use of unusual amino acids created strong interest in approaches to asymmetric syntheses of amino acids and methodological improvements in peptide synthesis as well as recent advances in purification and characterization methods."