TSR

TSR, Inc. (Tactical Studies Rules) was an American game publishing company, best known as the original publisher of Dungeons & Dragons (D&D). Its earliest incarnation was founded in October 1973 by Gary Gygax and Don Kaye. Gygax had been unable to find a publisher for D&D, a new type of game he and Dave Arneson were co-developing, so he founded the new company with Kaye to self-publish their products. Needing financing to bring their new game to market, Gygax and Kaye brought in Brian Blume in December as an equal partner. Dungeons & Dragons is generally considered the first tabletop role-playing game (TTRPG), and established the genre. When Kaye died suddenly in 1975, the Tactical Studies Rules partnership restructured into TSR Hobbies, Inc. and accepted investment from Blume's father Melvin.

From the Wikipedia article “TSR, Inc.”, licensed under CC BY-SA 4.0.

TSR is no longer an active publisher (defunct since 1997). Its books may still be in print through successor companies or available second-hand and in libraries.