Neuropsychology has presented a particularly formidable array of devel opments during recent years. The number of methods, theoretical ap proaches, and publications has been steadily increasing, permitting a step-by-step approach to a deeper understanding of the tremendously complex relationships existing between brain and behavior. This volume was planned as a collection of papers that, in one way or another, present new research and clinical perspectives or interpretations about brain-behavior relationships. Some chapters present new research in specific topics, others summarize the evidence for a particular the oretical position, and others simply review the area and suggest new perspectives of research. Consistent with the spirit in which the book was planned, the authors present and propose new avenues for developing neuropsychology and understanding the organization of cognitive activity. Part I is devoted to basic theoretical and technical approaches in studying brain organization of cognitive processes. Hanlon and Brown (Microgenesis: Historical Review and Current Studies) present an over view of some clinical and experimental work from the standpoint of mi crogenetic theory. Microgenesis is considered to be the structural devel opment of a cognition through qualitatively different stages. The authors discuss the growing dissatisfaction with both the old center and pathway theories and the newer modular or componental accounts. They also ex plore how micro genesis can be extended to the interpretation of symp toms of brain damage in developing a structural model of hierarchic levels through which the process of cognitive function unfolds.