Rosalind Franklin was a PhD scientist like the others who won the Nobel prize (Watson, Crick and Wilkins) for the discovery of the DNA double helix, but for various reasons she was treated like a lab technician. She was an expert in X-Ray crystallography which was the technique used to ultimately work out the structure of the double helix of DNA. Apparently she was an obstinate difficult type and did not agree at first that DNA was a double helix. You can find out more about Rosy and her relationship to the others in "The Double Helix" by James Watson which can be found in every library. There is a lot of information about Rosalind Franklin available on the Internet, for example, the UC San Diego website or the Access Excellence website.
Jill, from the Internet adds: "The main reason Rosy didn't receive the Nobel Prize along with Wilkins, Watson and Crick is that she had already passed away when the award was given."
Without Rosalind Franklin's work as a diffraction crystallographer, the DNA helix structure would never have been discovered. Her now infamous Slide 51 was taken from her.
She didn't receive the Nobel Prize for Science in '62 because it is never given posthumously but she was nominated for it on the year of her death, 1958. She died from ovarian cancer as she had spent all of her career working with X-rays unprotected. Also she found the nickname, "Rosy", that Crick, Watson, Pauling and Wilkins gave her as derogatory, which she hated.
[EDITOR: information is based on family stories.]