Land, Sea or Air?

The author recalls those occasions in European history when states had to choose whether to wage war on land, or on the sea, and latterly in the air as well. He describes the results of their decisions about allocating defence resources and considers whether a different mix of land, sea and air forces might have produced different results. This survey of defence strategy starts in 490 BC with the Persian invasion of Greece and ends with some remarks about strategic choices after the Cold War.