Simulations Publications, Inc. (SPI) was one of the biggest strategic
board gaming firms (up there with
Avalon Hill) during the 60's and 70's.
They published a bi-monthly magazine "Strategy & Tactics" (S&T) which included a full wargame every issue. They even started a sister publication of science fiction and fantasy games called "Ares".
However due to various problems and changes in the marketplace they ran into severe problems and were taken over by TSR in the early 80's. Due to TSR's heavy handed tactics towards S&T subscribers etc. They were driven into the ground.