Great Britain in the 1970s appeared to be in terminal decline--ungovernable, an economic wreck, and rapidly headed for global irrelevance. Three decades later, it is the richest and most influential country in Europe, and Margaret Thatcher is the reason. The preternaturally determined Thatcher rose from nothing, seized control of Britain's Conservative party, and took a sledgehammer to the nation's postwar socialist consensus. She proved that socialism...