This biography looks to the 1780s—the Age of the Constitution—to investigate the rise of a radical new idea in the English-speaking world: female genius. The perfect exemplar of this was Eliza Harriot Barons O’Connor, the pathbreaking educator who delivered a University of Pennsylvania lecture attended by George Washington. Harriot brought the concept of female genius to the United States and argued that women had equal capacity and deserved an equal education and political representation. In recovering this pioneering life, the Female Genius makes clear that America’s framing moment did not belong solely to white men.