The symposium was held in honor of William R. Mehler and was focused on his interest in the forebrain, and included the forebrain's somatosensory afferent and its efferent motor pathways. The book reflects his interest in networks and systems which allow one to understand the functioning of a certain area of the brain. Innovative work done by Mehler on ascending pain pathways and on the thalamic afferent system is reviewed. The book is largely a review of work done on the physiological structure of the brain, the interplay between different parts of the brain and the effect of this on behavior and sensation. Although the functioning of the forebrain is not yet fully understood there has been enormous progress since the first papers from Bill Mehler in the 1950's, and the book offers a useful up-to-date overview of the topic.