Three scientists, George Wald, Ragnar Granit, and Haldan Keffer Hartline, were named last week to share the 1967 Nobel prize in medicine or physiology. Wald is professor of biology at Harvard University. Granit is retired director of the Neurophysiological Institute of the Royal Medical School in Stockholm; at present he is serving as a visiting professor at St. Catherine's College in Oxford. Hartline is professor of biophysics at Rockefeller University. The following are appreciations and descriptions of Wald's work by John E. Dowling and of Granit's and Hartline's work by Floyd Ratliff.