Dungeons and Dragons

Dungeons & Dragons is a fantasy tabletop role-playing game originally designed by Gary Gygax and Dave Arneson, and first published in 1974.

The game has been published by Wizards of the Coast (now a subsidiary of Hasbro) since 1997. It was derived from miniature war games with a variation of the Chainmail game serving as the initial rule system.

It's publication is commonly recognized as the beginning of modern role-playing games and the role-playing game industry.

It has had a large effect on fantasy, simultaneously adding huge numbers of new readers but also by tuning that audience towards dreary potboiler quest fantasies turned out by the hundreds by publisher like TSR.