There are numerous biographies of Margaret Thatcher, but as yet no full-length study has been written by a political scientist. This is a disappointing omission from the literature, and reflects a general tendency to undervalue biographical studies. One result has been the production of scholarly work on the Conservative party between 1975 and 1990 which is unduly abstract and often misleading. Equally, although some excellent biographies have been produced – and Thatcher's memoirs are among the best of their genre – the unique perspectives of political science can yield some fascinating insights into her career, her party and the changing nature of British government. This article traces some of the crucial interactions which influenced Thatcher – her family background, her experiences within the Conservative party, her electioneering and her conduct of government. It concludes that although Thatcher's personality developed as a result of these encounters, as an adult she affected institutions far more than they affected her. This raises interesting, but not insuperable challenges for political scientists. Individuals do matter, and their influence can be appraised within a broader context. Ironically, it seems that complex characters conform more readily to generalisable norms of political conduct; Thatcher, by contrast, broke many of the accepted rules precisely because her personality was so banal.