The paper describes a cybernetic computer-based instructional system, SOCRATES, the teaching model which led to its development, and some of the research accomplished with it. The acronym, SOCRATES, is System for Organizing Content to Review and Teach Educational Subject. It consists of a group of student input-output (I/O) stations wired to a digital computer through a relay rack. It is a computer-based tutorial system designed to meet the requirements of an idiographic contingency model of the instructional process, which, therefore, makes it possible to provide highly adaptive individualized instruction to several students simultaneously. The model defines the presumably critical dimensions of instruction and treats these as system functions. The system permits controlled implementation of the model as well as the collection of data which could lead to its further development. (Author)