A description is provided of the design and development of an author language for computer-assisted instruction (CAI). This Teaching and Coursewriting Computer Language (TACL) is described as being easy to learn for newcomers to computers and as providing efficiency and time savings in course development without sacrificing power or flexibility. Individual chapters of the report discuss: 1) general aspects of CAI; 2) programing languages for CAI course design; 3) the computer science aspects of CAI author languages; and 4) the implications of TACL. (Author/PB)