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 three of the most respected figures in British public life--Roy Jenkins, David Owen, and Shirley Williams. But 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 in-fighting...