TSR Produced three editions of Top Secret. The 1st and 2nd editions were largely compatible - being released in 1980 and 1981 respectively.
In 1987, Top Secret/S.I. (Special Intelligence) was released.
Top Secret is an espionage-themed role-playing game written by Merle M. Rasmussen and first published in 1980 by TSR, Inc.
Source: Wikipedia, "Top Secret (role-playing game)", available under the CC-BY-SA License.