Rosalind Elsie Franklin (25 July 1920 – 16 April 1958) was a British biophysicist and X-ray crystallographer who made critical contributions to the understanding of the fine molecular structures of DNA (deoxyribonucleic acid), RNA, viruses, coal, and graphite. Her DNA work achieved the most fame because DNA plays an essential role in cell metabolism and genetics, and the discovery of its structure helped her co-workers understand how genetic information is passed from parents to their offspring.Franklin is best known for her work on the X-ray diffraction images of DNA which led to the discovery of the DNA double helix. According to Francis Crick, her data was key to determining the structure to formulate Crick and Watson's 1953 model regarding the structure of DNA. Franklin's images of X-ray diffraction confirming the helical structure of DNA were shown to Watson without her approval or knowledge. This image provided valuable insight into the DNA structure, but Franklin's scientific contributions to the discovery of the double helix are often overlooked.Unpublished drafts of her papers (written just as she was arranging to leave King's College London) show that she had independently determined the overall B-form of the DNA helix and the location of the phosphate groups on the outside of the structure. Moreover, it was a report of Franklin's that convinced Crick and Watson that the backbones had to be on the outside, which was crucial since before this both they and Linus Pauling had independently generated non-illuminating models with the chains inside and the bases pointing outwards. However, her work was published third, in the series of three DNA Nature articles, led by the paper of Watson and Crick which only hinted at her contribution to their hypothesis.After finishing her portion of the work on DNA, Franklin led pioneering work on the tobacco mosaic virus and the polio virus. She died in 1958 at the age of 37 of ovarian cancer.