Simulations Publications, Inc. (SPI) was an American publisher of board wargames and related magazines, particularly its flagship Strategy & Tactics, in the 1970s and early 1980s.
TSR began selling SPI's inventory in 1982, but later acquired the company's trademarks and copyrights in 1983 and continued a form of the operation until 1987.
Upon his return to civilian life in 1964, Dunnigan began to contribute articles to Avalon Hill's house publication The General and independent wargaming magazine Strategy & Tactics.
In one of his contributions to The General, Dunnigan criticized what he saw as a lack of historical accuracy in Avalon Hill's 1965 release, Battle of the Bulge.
Thomas Shaw, at the time in charge of Avalon Hill, asked Dunnigan to design and submit his own wargame.
Two years later, after designing 1914 for Avalon Hill, Dunnigan struck out on his own after concluding there must be a "more effective way to publish games.
This advertising campaign led to a much larger subscriber base and SPI came to be seen as a serious competitor to Avalon Hill, the company that had founded the board wargaming hobby.
To handle the increased sales, SPI formed a formal British subsidiary, Simpubs Ltd. in June 1976.
A typical early game came in an envelope with only a one-color map and one large folded sheet for the rules.
However, SPI quickly set about improving the physical quality of the components with better printing and boxes under the guidance of Art Director Redmond A. Simonsen.
[5] SPI had shopped for venture capital providers to take advantage of the perceived expansion of the gaming market in the late 1970s.
SPI negotiated a promissory note loan (at the time mentioned as $225,000 but here listed as $400,000 from TSR (the publishers of Dungeons & Dragons).
TSR originally claimed they acquired SPI, but as that would mean they also would be responsible for their debts, quickly changed that statement.