In this groundbreaking new biography, based on more than ten thousand hitherto unavailable letters and diary entries, bestselling author Niall Ferguson returns to his roots as a financial historian to tell the story of Siegmund Warburg, an extraordinary man whose austere philosophy of finance offers much insight today. A refugee from Hitler's Germany, Warburg rose to become the dominant figure in postwar City of London and one of the architects of European financial integration. Seared by the near collapse and then "Aryanization" of his family's long-established bank in the 1930s and then frustrated by the stagnation of its Wall Street sister, Kuhn Loeb, in the 1950s, Warburg resolved that his own firm of S. G. Warburg (founded in 1946) would be different. An obsessive perfectionist with an aversion to excessive risk, Warburg came to embody the ideals of the haute banque-high finance-always eschewing the fast buck in favor of gilt-edged advice. He was not only the master of the modern merger and founder of the eurobond; he was also a key behind-the-scenes adviser to governments in London, Tokyo, and Jerusalem-to his critics, a "financial Rasputin." Like a character from a Thomas Mann novel, Warburg was a complex and ambivalent man, as much a psychologist, politician, and actor-manager as he was a banker. In High Financier, Ferguson shares the first book-length examination of a man whose life and work suggest an alternative to the troubled business principles that helped shape our current financial landscape.