Launched on a wave of euphoria in 1981, the SDP aroused the hopes and enthusiasm of millions of people. Promising to break the mould of British politics, its leaders included four of the most respected figures in British public life - Roy Jenkins, David Owen, Shirley Williams and Bill Rodgers. But the SDP failed. Despite winning, with the Liberals, a quarter of the vote in two general elections, by the autumn of 1987 it had disintegrated amidst acrimony and bitter infighting. This book, based on unprecedented access to the SDP's archive, analyses in detail the reasons for its early success and its ultimate demise.