Several writers have remarked that Marlborough could have never achieved his great military success during the War of the Spanish Succession without the support, industry and ingenuity of his Chief of Staff, Quartermaster General and Chief of Intelligence, General William Cadogan, who became the 1st Earl of Cadogan, and who, in 1722, succeeded Marlborough as Commander-in Chief of the British Army. Apart from the other considerations, Marlborough, then in his 50's, was relatively frail and prone to fevers and headaches, whereas Cadogan, the better educated officer, was still in his early 30's and very fit. This, the story of a most able young general, is a must for all those interested in military history, particularly that relating to the early 18th century. However, Cadogan was a more complex -and more interesting -personality than his career as a soldier indicates. He possessed the charm, the wisdom, the powers of persuasion and the linguistic ability to make an outstanding diplomat. He proved, indeed, to be the brightest roving ambassador of the reign of George I. And yet, despite all his positive attributes he was not a political man, nor one of financial integrity.