Book excerpt: This elegant book presents current evidence on the organization of the mammalian cerebral cortex. The focus on synapses and their function provides the basis for understanding how this critical part of the brain could work. Dr. White and his colleague Dr. Keller have collated an impressive mass of material. This makes the crucial information accessible and coherent. Dr. White pioneered an area of investigation that to most others, and occasionally to himself, seemed a bottomless pit of painstaking at tention to detail for the identification and enumeration of cortical syn apses. I do not recall that he or anyone else suspected, when he began to publish his now classic papers, that the work would be central to an accelerating convergence of information and ideas from neurobiology and computer science, especially artificial intelligence (AI) (Rumelhart and McClelland, 1986). The brain is the principal organ responsible for the adaptive capacities of animals. What has impressed students of biology, of medicine, and, to an extent, of philosophy is the correlation between the prominence of the cerebral cortex and the adaptive "complexity" of a particular spe cies. Most agree that the cortex is what sets Homo sapiens apart from other species quantitatively and qualitatively (Rakic, 1988). This is summarized in the first chapter.