The philosophy department of the Ohio State University began development of a computer-tutorial program, called ENIGMA, in 1972. The aim of the course was to help students to use various logical tools in the analysis of everyday arguments by giving drill-and-practice sessions, testing, and grading examinations. Part of ENIGMA is the propositional argument program which is able to abstract the relevant syntactical form from the student's natural language response and check the response for logical mistakes, gross spelling errors, and violations of propositional integrity. This program can be used in a test as well as a tutorial format. A program for categorical syllogisms has a feature offering the capability of using Venn diagrams to determine validity. The programing language for ENIGMA is Coursewriter II; it is timeshared on an IBM 370/158. It is expected that by spring of 1976 approximately 1,000 students per quarter will use the program. (JY)