This document provides an overview of the wargame Advanced Squad Leader (ASL). It summarizes the game's origins in 1977-1985 under Multi-Man Publishing, its detailed scale that simulates squad-level combat, and its unique turn sequence that includes phases for movement, different types of fire, rout, advance, and close combat. It also notes some of the game's capabilities for historical simulation and comparison to other wargames, and provides resources for learning more.