Rosalind Franklin (London, 1920 – 1958), a chemist and crystallographer at King's College London, produces in May 1952 Photograph 51 through high-resolution X-ray crystallography: the sharpest image obtained until then of the B form of DNA. The image clearly shows the molecule's helical geometry and allows its key dimensional parameters — diameter, helical pitch, and distance between bases — to be calculated. Franklin did not authorize its use outside the laboratory. In January 1953, Maurice Wilkins showed the photograph to James Watson without Franklin's knowledge or consent. Watson describes in The Double Helix (1968) the moment he saw the image: "my mouth fell open and my pulse began to race." Together with a confidential Franklin report that Wilkins also shared without permission, this data was decisive for Watson and Crick's proposal of the correct structure in April 1953. Franklin died of ovarian cancer in 1958, four years before the Nobel Prize awarded to Watson, Crick, and Wilkins in 1962. The Nobel Prize is not awarded posthumously.