Skirmisher Publishing LLC is an Alexandria, Virginia-based publisher of wargames, roleplaying games, and historic reprints. It was founded by author, editor, and game designer Michael J. Varhola and is co-owned by Robert "Mac" McLaughlin and Geoffrey Weber. About half of Skirmisher's products have been published under the d20 System, a system of game mechanics for role-playing games published in 2000 by Wizards of the Coast that is based on the third edition of Dungeons & Dragons and named after the 20-sided die which is central to the core mechanics of the system.