It began in 1966 as a wargaming fanzine published by Chris Wagner (then a staff sergeant with the US Air Force in Japan), at first in Japan, then moving to the United States with Wagner. It was intended as independent competition with the Avalon Hill house magazine The General.
Dunnigan made some radical changes. Starting with issue 20, each issue contained a complete new wargame. Not only did this represent a break from the cautious AH policy of publishing one or two games per year (for fear of new games cannibalizing sales of old ones, an odd concern since both their new and old games sold for about the same price), but the need for new game designs spurred research into many of the lesser-known corners of military history.
Another innovation of the magazine was its feedback system, in which readers would answer various multiple-choice questions on a return card, whose data would then be entered into a Burroughs minicomputer for analysis. Thus S&T always had good information about which games readers were looking for.
In addition to the games, the magazine featured many insightful articles on military history, many of them notable for applying modern quantitative analysis to battles that had traditionally been described in a narrative "heroic" style.
However, SPI mismanagement in the late 1970s resulted in its assets being bought by TSR in 1982, including S&T, which at that point had 30,000 subscribers. After several years (issues 91 to 111), TSR sold S&T to 3W, who published issues 112 to 139 before selling it to Decision Games, which was still publishing it in 2003.
Back issues of Strategy & Tactics are today valued by wargame collectors, and some of them have seen steadily rising prices in the wargame market.