The original Top Secret roleplaying game product line had been dormant for a couple of years when Top Secret/S.I. released in 1987. The classic game had sold moderately-well from its inception in 1980 through the last modules in 1985.
TSR clearly believed TS/SI would be a hit, publishing 2 box sets and 16 accessory books over the next 3 years, plus several related books and graphic novels. After 1990, though, everything came to a halt, and TS/SI became a historical RPG footnote.
This post will focus on unpacking the TS/SI core box set. To see all the supplements, see my RPG reference site page.
Top Secret SI was a completely different game system than the original black box. It did retain the percentile attributes, but skills are based on ranks, for example. Hit points are assigned to body locations. The primary background setting of TS/SI was based on fictional supranational organizations Orion & Web, locked in contentious global competition. However, several of the supplements expanded campaign choice beyond that dyad: F.R.E.E. Lancers (cybernetics), Agent 13 (pulp WWII), and the real world of espionage in the Eighties.

Top Secret/S.I. [BOX SET]
1987 … Doug Niles … TSR 7620 … ISBN 0880384077
BOX CONTENTS:
* 96-page Players Guide
* 64-page Administrators Guide
* 24-page Settings and Scenarios booklet
* 16-page Equipment Inventory booklet
* Location map
* Sheet of cut-out figures
* Six-panel Administrator’s Screen
* Character Dossiers (in the Equipment booklet)
BOX


Players Guide






The art in TS/SI is lackluster, with the best pieces being the recycled illustrations from the previous edition.
TSR didn’t use their piece ID system in TS/SI. If they had, the set parts would have labelled 7620XXX0701 for the first map, 7620XXX1901 for the first book, etc. These are real handy when IDing loose parts. TSR would use this piece code system for years after 1990, so I don’t know the reason for its omission here.
Administrators Guide






Settings and Scenarios


Equipment Inventory



The Equipment booklet has the character sheets in the center.
The gear line art is quite good.
Character Dossiers



Location map






The large blueprint style location poster map is printed on both sides, filled with typical encounter spots like Apartment, Airport, Train cars, etc.
Administrator’s Screen


Three-panel GM / Ref screen, printed on both sides.
Sheet of cut-out figures

See Also:
I never played the original Top Secret, but we picked up this one when it came out. I totally agree about the art. At first I thought the game and all its rules were very cool, but I found it too cumbersome when it actually came to play time.
Seems like this came out about the same time as Gamma World 3rd Ed., which had almost no interior art at all, and would’ve been improved by recycling some illustrations from the older version. TSR must’ve been cutting its art budget.
My favorite game system of all time. Once you knew the rules it was fast and deadly. I’m disappointed there are not more retro clones of it out today but guys over at DWD studios put out some good stuff building off the spirit of TSSI.