Effective teaching is a multifaceted endeavor comprised of process, product, artistic, and scientific aspects. The scientific dimension pertains to that multidisciplinary accumulation of systematic knowledge which makes possible the prediction and control of human behavior as it relates to the events comprising instruction and learning. This paper suggests that any responsible discussion of the science of teaching must give serious consideration to those contributions made by (1) the conceptual, functional, and research dimensions of mastery learning, and (2) those points of merger between mastery learning and instructional psychology known as instructional design, conditions of learning, student learning styles, and models of teaching. (Author)