‘O’ Group is a set of WWII battalion level rules designed for a player to command a battalion sized force plus supports, or a multiplayer game where each player can command a battalion as part of a larger battlegroup.  The rules introduce some exciting command mechanisms that encourage the players to think about allocation of reserves as well as commanding their force in action.  The rules include army lists covering the UK, USA, Germany and Soviet Union for the later war period but the rules can be used with historical unit structures to game the entire conflict.  This soft cover, perfect bound rule set is 106 pages on length.