Publisher Summary Cajal's Histology of the Nervous System is very likely to contain more information about animal brains than any other text of neurology. One notices three astonishing facts about this book: this information is to a large extent unrelated to current physiological research, since Cajal's detailed description of the histology of many types of grey substance has no equally detailed physiological analysis to match it; no matter how rich in details, the book is really a sketchy account of the immense variety of neurological structures and is not likely to contain an answer to any particular question about some particular structure in some particular species of animals; the book contains reliable pictures but is nearly devoid of quantitative indications. Some aspects are discussed of histology, histonomy and histologics in relation to cybernetics. Isolated aspects of the logics can be inferred from aspects of the histology (types of symmetry, maximum logical depth possible, and degree of complexity). In some cases (cerebellar cortex) inspection and intuition may suffice to produce plausible logical schemes. In the case of the cerebral cortex which will be illustrated with material from our own Golgi analysis, one has to be contented with partial insights.