Rosalind Franklin was an English chemist and crystallographer, whose X-ray diffraction studies contributed to the double helix model of the molecular structure of DNA.

Franklin had studied physical chemistry at Newnham College, Cambridge, although as a woman she was not allowed to graduate. She received her PhD in 1945 for research into the small-scale structures of coal and carbons, undertaken during the Second World War. As a postdoctoral researcher in Paris, she became familiar with the use of X-ray diffraction as a method for analysing molecular structures. Working at King's College London from 1951 to 1953, she applied this technique to DNA.

Under Franklin's direction, an X-ray photograph 'Photograph 51' was captured which provided key information that was crucial for developing an understanding of the structure of DNA. Without her knowledge, this photograph and a report on her work were passed on to Francis Crick and James Watson at the Cavendish Laboratory in Cambridge. The information helped the two Cambridge researchers to develop the double-helix model of DNA.

Later in her career Franklin investigated other structures, especially the tobacco mosaic virus. Her life was tragically cut short when she was diagnosed with ovarian cancer in 1956, and she died in 1958.