In 1911, some of the greatest minds in science convened at the First Solvay Conference in Physics. Over the course of those few days, these figures began to realize that classical physics was about to give way to quantum theory, a seismic shift in how we understand the universe. Despite her formidable achievements, Marie Curie remained a marginal figure, not least because of an alleged affair with a fellow scientist. After a meeting with the young Albert Einstein, Curie's fortunes changed, Jeff Orens suggests here, because she had met a thinker brilliant enough to understand her, and resolute enough to offer his support.