On April 19, 1906, the forty-seven-year-old Nobel laureate Pierre Curie was run over by an oversize, horse-drawn wagon filled with bales of army uniforms. He was negotiating that tricky Parisian intersection where traffic from the rue Dauphine, the quai Conti, the quai des Grands Augustins, and the pont Neuf have created Gallic havoc for over a century. Curie had just quit a meeting of reform-minded University professors where he argued for legislation to improve the lot of junior faculty and to prevent laboratory accidents. He had planned to stop at his publisher’s office on the quai, but because of a strike—by equally reform-minded trade unionists—the office was shut. Absent-minded and somewhat radium-sick, he turned away in the spring rain, and was on his way to the library of the Institut when that six-ton wagon rumbled down the bridge from the Ile de la Cité to crush his skull.

His death brought to an end two remarkably creative careers in physical science, his own and that of his wife, Maria Salomea Sklodowska—known to the world as Madame Curie. She later recollected that on the rue Dauphine “I lost my beloved Pierre, and with him all hope and all support for the rest of my life.” She was right: for although Madame Curie was to survive her husband until 1934, her contributions to science after his death were less than innovative; she turned her tough mind to the application of their discoveries, to teaching young scientists, and to construction of