Dungeons & Dragons (abbreviated as D&D or DnD) is a fantasy role-playing game (RPG) published by Gary Gygax and David Arneson in January 1974. It was first published by Gygax's company, Tactical Studies Rules (TSR), and subsequently spawned the RPG industry. D&D is by far the best-known and best selling RPG, with an estimated 20 million players, many translations and over $1 billion in book and equipment sales (as of 2004).

After TSR floundered in 1996, Wizards of the Coast acquired the company in 1997, including all rights to D&D. Two years later, Wizards was purchased by Hasbro. Owing partially to heavy marketing, products branded Dungeons & Dragons made up over fifty percent of the RPG products sold in 2002.

The current edition of Dungeons & Dragons is the 4th edition. The game was the first to use the d20 system mechanic and open gaming license (up until 3.5 edition, this was the license used by Wizards of the Coast). The 4th edition was released under the game system license.

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