A project studied the problem of control of skilled motor movements by concentrating on typing. The fundamental phenomena of typing, which fall into three categories, were reviewed: timing of key strokes, pattern of errors, and general organization of typing. A model for the simulation of these phenomena was developed, based on an Activation-Trigger-Schema system. In this system a hierarchical structure of schemata directs the selection of letters to be typed and then controls the hand and finger movements by a cooperative, relaxation algorithm. The interactions of the patterns of activation and inhibition among the schemata determine the temporal ordering for launching the keystrokes. The model exists as a working computer simulation and produces an output display of the hands and fingers moving over the keyboard. It reproduces some of the major phenomena of typing, including the interkeypress latency times, pattern of transposition errors found in skilled typists, and doubling errors. Appraisal of the model found it to be clearly inadequate or wrong in some of its features and assumptions, but the model served as a useful first approximation for the understanding of skilled typing. (Author/YLB)