"Dungeons & Dragons (abbreviated as D&D or DnD) is a fantasy role-playing game (RPG) originally designed by Gary Gygax and Dave Arneson, and first published in 1974 by Tactical Studies Rules, Inc. (TSR). The game has been published by Wizards of the Coast since 1997. It was derived from miniature wargames with a variation of the Chainmail game serving as the initial rule system. D&Ds publication is widely regarded as the beginning of modern role-playing games and the role-playing game industry
Seventy-three unique digital games had been released and sold under the D&D license as of May 2006[update]. Almost half of these games were published by Strategic Simulations, Inc. (SSI). Most, but not all, are computer role-playing games that use rules derived from some version of the D&D rules. Many of the games were released on multiple platforms, including personal computers, consoles and handheld devices (including mobile phones).
Source: Wikipedia, "Dungeons_&_Dragons", available under the CC-BY-SA License.