This introduction presents an overview of the key concepts discussed in the subsequent chapters of this book. The book is concerned with the long dark period in currency history — from May 1940 until the late 1950s — during which only the dollar and Swiss franc survived as 'hard monies'. It explores history of the events leading up to the floating of the mark on May 5 1971 — the Bastille Day for the Bretton Woods system. The book also explores contemporary history of international money movements through the modern era. The Bonn-Washington conflict on policy was only one of the elements in the final crisis of Bretton Woods. At least of equal importance was the increasing trade friction between the USA and Japan. Fast-growing imports — particularly of colour televisions and automobiles — at a time of weakness in the US economy was providing powerful ammunition to the protectionists in Washington.