A tri-level structure of cognitive operations in concept learning is proposed, based on results of controlled experimentation and factor analytic studies. Global strategies in concept attainment are hypothesized to consist of three phases: attending to the situation, searching for information, and processing and using the information. Further, specific cognitive operations entailed in each of the three phases are identified. Research related to the structure and to each of the operations is summarized. Clarification of the cognitive operations in concept learning may lead to a better understanding of individual differences in learning, provide a theoretical basis for a process approach to the curriculum, and suggest variables which may be effective in facilitating concept learning. (Author)