Strategy & Tactics got its start in January 1967 under the auspices of its original editor, Chris Wagner, offering what he saw as a better alternative to Avalon Hill's gaming magazine, The General. Strategy & Tactics began life as a wargaming fanzine published by Wagner (then a staff sergeant with the US Air Force in Japan), at first in Japan, then moving to the United States with Wagner.
Graphic designer Redmond Simonsen was hired to improve the quality of the 'zine. When subscribership stagnated, debts began to accrue. Jim Dunnigan created SPI in order to save Strategy & Tactics. Dunnigan had been a contributor to the magazine since Strategy & Tactics #2 (February 1967), and when Wagner was having financial difficulties with the magazine he sold Dunnigan the rights for $1. After SPI's demise publishing passed first to TSR, then later 3W and finally Decision Games, who is still publishing it.
Further resources pertaining to Strategy & Tactics magazine and Wargames in general may be found at Grognard.com