This is the collection of 26 papers presented at the symposium. The majority of papers are in English translation and a few in the original English and French. Most papers are of a distinct value to the readers interested in the problems of the development of cerebral functions. The bulk of papers are from large centers of research in the USSR. Some of the papers seem to have suffered somewhat in their rendition into English. However, most papers are instructive and some set forth challenging problems for further investigation and experimental control. Such, for example, is the evidence presented by Kogan and associates for the capacity of cerebral cortex in young animals to "regenerate" after extensive ablations. Two papers, one by Flexner on "The Molecular Basis for Change in the Catalytic Activity During Cerebral Development" and the other by Pigareva on "The Development of Oxidative Enzyme Systems at Different Levels