Unearthed Arcana

Unearthed Arcana (abbreviated UA) is the title shared by two hardback books published for different editions of the Dungeons & Dragons fantasy role-playing game. Both were designed as supplements to the core rulebooks, containing material that expanded upon other rules.

The original Unearthed Arcana was written primarily by Gary Gygax, and published by game publisher TSR in 1985 for use with the Advanced Dungeons & Dragons first edition rules. The book consisted mostly of material previously published in magazines, and included new races, classes, and other material to expand the rules in the Dungeon Masters Guide and Players Handbook. The book was infamous for its considerable number of errors, and was received negatively by the gaming press whose criticisms targeted the over-powered races and classes, among other items. Gygax intended to use the book's content for a planned second edition of Advanced Dungeons & Dragons; however, much of the book's content was not reused in the second edition, which went into development shortly after Gygax's departure from TSR.

A second book using the Unearthed Arcana title was produced by Wizards of the Coast for Dungeons & Dragons third edition in 2004. The designers did not reproduce material from the original book, but instead attempted to emulate its purpose by providing variant rules and options to change the game itself. A reviewer for RPGnet noted that while this book was filled with ideas and suggestions, he found little that he actually wanted to use.