Advanced Squad Leader (ASL) is a complex wargames system that traces its roots back to the late 1970s. Quality comes with time and ASL is the fruition of years of research and development, and thousands of hours of playtesting.
ASL simulates the excitement and tension of platoon, company and or even battalion level tactical combat from every theatre of World War II. Counters represent squads (typically ten soldiers), half squads or crews.

Individual leaders, heroes, vehicles and guns are also represented. Units from every major or minor nation that took part in WWII can be depicted.
Players strive to gain the advantage through the fire and movement of their forces, using geomorphic mapboards and terrain overlays to represent battlefields for particular scenarios. Over 1,200 plus scenarios - based on parts of actual battles or skirmishes - are available.
Scenarios cover a diverse range of different tactical situations, designed to test the skill and nerve of players. As in life, luck may influence parts of a game and new players soon learn why rolling a Double One may be critical!
At the heart of ASL is its well structured and comprehensive rule book - the ASLRB - with its chapters on infantry combat, terrain, guns and artillery, tanks, other vehicles, and more. The ASLRB is published by ASL's official publishers - Multiman Publishing (MMP). Chapter dividers provide many rule references and easy access to key tables for maintaining the flow of play. And there's also a detailed and concise index to enable players to find the details they need fast.
More recently, MMP have produced ASL starter kits 1 and 2 to introduce novice players to the enjoyment of the ASL system.

ASL even allows players to design their own scenarios using the many detailed historical notes that come with the ASLRB.
You could play ASL for the rest of your life and still not explore every element of this system, but if you're keen you'll have a lot of enjoyment along the way and probably make some friends too.