David Lance "Dave" Arneson (October 1, 1947 – April 7, 2009) was an American game designer best known for co-developing the first published role-playing game (RPG), Dungeons & Dragons, with Gary Gygax, in the early 1970s. Arneson's early work was fundamental to the development of the genre, developing the concept of the RPG using devices now considered to be archetypical, such as adventuring in "dungeons", using a neutral judge, and having conversations with imaginary characters to develop the storyline.