The evolving systems approach (ESA) addresses the need for direct study of the creative process in recognized creators at work, in contrast to indirect methods, such as those used in psychometric studies. The ESA emerged from H. E. Gruber's prolonged study of Charles Darwin's manuscripts, especially the notebooks he kept after the Beagle voyage. Gruber's interviews with J. Piaget about the latter's creative processes, as well as many doctoral dissertations, also helped shape the authors' approach. Using Gruber's (1974/1981) study of Darwin, the authors describe some facets of creative work identified in the course of their work. Among these are networks of enterprise, ensembles of metaphors, insights, and evolving belief systems. Although the ESA emphasizes cognitive processes, social, affective, and esthetic aspects of the case are not neglected. Each creative case is unique, otherwise the individual would not meet the criterion of originality. Uniqueness does not mean isolation; people who differ must and do work together. The integration of all these facets into a plausible system for each creator remains the authors' central task.