Investigators developed an on-line, interactive programing system--the Teacher-Interactive Computer System (TICS)--to provide assistance to those who were not programers, but nevertheless wished to write interactive instructional programs. TICS had two components: an author system and a delivery system. Underlying assumptions were that instructional programs required complex logical structures and could not be written in one linear sequence, that they must be modifiable, that authors should be able to use on- and off-line modes, that programs required communication with and some control by students, and that programs should allow different modes of interaction. TIC's structural framework consisted of interconnected nodes, each containing a linear sequence of actions. A dynamic data base was maintained and the author language served as the interface between the author and the system's routines: for creating, mapping, testing, and modifying programs, for viewing their structures, and for developing auxiliary information stores. Automatic maintenance features included space allocation for the growing data base, the assignment of identifiers for new items, and the notation of errors. (PB)