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 is currently published by Wizards of the Coast, a subsidiary of Hasbro. It was derived from miniature wargames with a variation of the Chainmail game serving as the initial rule system. D&D’s publication is widely regarded as the beginning of modern role-playing games and, by extension, the entire role-playing game industry.

Players of D&D create characters that embark upon imaginary adventures within a fantasy setting. A Dungeon Master (abbreviated as DM, also known as a Game Master or GM) serves as the game’s referee and storyteller, while also maintaining the setting in which the adventures occur. During each game session, the players listen to descriptions of their character’s surroundings, as well as additional information and potential choices from the DM, then describe their actions in response. The characters form a party that interacts with the setting’s inhabitants (and each other). Together they solve dilemmas, engage in battles and gather treasure and knowledge. In the process the characters earn experience points to become increasingly powerful over a series of sessions. D&D departs from traditional wargaming and assigns each player a specific character to play instead of a military formation. Miniature figures or markers, placed on a grid, are sometimes used to represent these characters.

The early success of Dungeons & Dragons led to a proliferation of similar game systems, such as Tunnels and Trolls,Traveller and RuneQuest. Despite this competition, D&D dominates the role-playing game industry, enjoying a nearly unassailable market position. In 1977, the game was split into two versions: the simpler Dungeons & Dragons and the more complex Advanced Dungeons & Dragons (abbreviated as AD&D or ADnD). AD&D 2nd Edition was published in 1989. In 2000, the simpler version of the game was discontinued and the complex version was renamed simply Dungeons & Dragons with the release of its 3rd edition. Dungeons & Dragons version 3.5 was released in June 2003, with a 4th edition in June 2008.