Among those statesmen who reached the peak of British politics in this century, Bonar Law remains the least known. A Canadian-born Glasgow businessman, he entered politics in 1900; within four years he was a member of Balfour’s government, and by 1911 he was the head of the Conservative Party. In the twelve years that followed, he reunited and reorganized the party following three electoral defeats, thus preparing the party for the century of frequent electoral success that lay ahead. During World War I, Bonar Law put aside party differences to cooperate with the Liberal Lloyd George, becoming virtually co-premier with the ingenious Welshman, whose reputation as “the man who won the war” owes much to their alliance. The cooperation of Conservatives and Liberals prospered until Bonar Law’s retirement in 1921, when tensions between the parties led to the end of the coalition. In 1922, the Conservatives turned again to him, and although his health was poor, he agreed to take the premiership, thereby definitively removing Conservatism from Lloyd George’s shadow. Under his skillful direction, one of the most abrasive and enduring problems of British politics was resolved: the division of Ireland was finally effected. Though in public Bonar Law was one of Unionism’s “hard men,” behind the scenes he struggled for a compromise acceptable to Ulstermen, Irish Nationalists, and the British parties, a compromise that led to the separation of Northern Ireland. In this illuminating biography, the first in more than forty years, the author refutes the hard-faced and shadowy image that has long represented Bonar Law. In its place, the author reveals an effective political leader who mastered his party and the House of Commons as few others had done, while at the same time becoming one of the best loved men in the House by colleagues of all parties. Bonar Law is also shown to be a complex and tragic person—a passionate husband, an indulgent father, and a generous friend—who was nonetheless a lifelong depressive whose private life was cursed by terrible losses.