For 31 years, "Progress in Psychobiology and Physiological Psychology" has provided cutting-edge literature to behavioral neuroscience research. Volume 18 includes four original chapters covering a broad range of contemporary topics in behavioral neuroscience. In the first of these, Alan Rosenwasser skillfully reviews the current status of the rapidly developing field of circadian neurobiology. He focuses on the mammalian suprachiasmatic nucleus system emphasizing inputs to the 'clock', their neurochemical phenotype, and outputs from the 'clock' to behavioral and other effector systems....