The most challenging military actions are often combined operations which involve the combination of all elements of air, sea and land power. Although the mechanics and technology of combined military operations have been refined and developed over time, the actual principles and rules governing successful operations still follow traditional lines. This work examines four complex invasions - Quebec 1759, Gallipoli 1915, Inchon 1950 and the Falklands 1982 - in terms of preparation, assault, consolidation and breakout.