Abstract: Part I: Historical Perspectives. Proopiomelanocortin and the Melanocortin Peptides, A. N. Eberle. Melanocortins and Pigmentation, A. B. Lerner. Melanocortins and Adrenocortical Function, M. Begeot and J. M. Saez. Effects of Melanocortins in the Nervous System, R. A. H. Adan. Peripheral Effects of Melanocortins, B. A. Boston. Part II. Characterization of the Melanocortin Receptors. Melanocortin Receptor Expression and Function in the Nervous System, J. B. Tatro. Cloning of the Melanocortin Receptors, K. G. Mountjoy. Part III. Biochemical Mechanism of Receptor Action. The Molecular Pharmacology of Alpha-Melanocyte Stimulating Hormone: Structure-Activity Relationships for Melanotropins at Melanocortin Receptors, V. J. Hruby and G. Han. In Vitro Mutagenesis Studies of Melanocortin Receptor Coupling and Ligand Binding, C. Haskell-Luevano. Part IV. Receptor Function. The Melanocortin-1 Receptor, D. Lu, C. Haskell-Luevano, D. I. Vage, and R. D. Cone. The Human Melanocortin-1 Receptor, E. Healy, M. Birch-Machin, and J. L. Rees. The Melanocortin-2 Receptor in Normal Adrenocortical Function and Familial Adrenocorticotropic Hormone Resistance, A. J. L. Clark. The Melanocortin-3 Receptor, R. A. Kesterson. The Melanocortin-4 Receptor, R. D. Cone. The Melanocortin-5 Receptor, W. Chen. Part V. Receptor Regulation. Regulation of the Melanocortin Receptors by Agouti, W. O. Wilkison. Melanocortins and Melanoma, A. N. Eberle, S. Froidevaux, and W. Siegrist. Regulation of the Mouse and Human Melanocortin-1 Receptor, Z. Abdel-Malek. Part VI. Future Vistas. Future Vistas. R. D. Cone. Index.