Training in computer literacy of some form, much of which will consist of training in computer programming, is likely to involve $3 billion of the $14 billion to be spent on personal computers by 1986 (Harmon, 1983). Who will do the training? "hardware and software manufacturers, management consultants, -retailers, independent computer instruction centers, corporations' in-house training programs, public and private schools and universities, and a variety of consultants" (-ibid. , p. 2 7 ) . To date, very little is known about what one needs to know in order to learn to program, and the ways in which educators might provide optimal learning conditions. The ultimate success of these vast training programs in programming - especially toward the goal of providing a basic computer programming competency for all individuals - will depend to a great degree on an adequate understanding of the developmental psychology of programming skills, a field currently in its infancy. In the absence of such a theory, training will continue, guided - or to express it more aptly, misguided - by the tacit "folk theories" of programming development that until now have served as the underpinnings of programming instruction. Our paper begins to explore the complex agenda of issues, promise, and problems that building a developmental science of programming entails.