Military historian John Colvin examines the battles throughout the centuries that can be said to be decisive, in that they affected not just immediate events but also the final outcome of a war and even beyond. From Salamis in 479 BC, when Themistocles' Athenians defeated the Persians led by Xerxes, through Hastings, Saratoga and Trafalgar to the major conflicts of the 20th century, Colvin assesses the wider implications of each victory, or defeat, giving it its proper place in the context of human history. The Battle of Britain, for example, was not only a turning-point in World War II, but also prevented the invasion of Britain and German hegemony in Europe.