An aggressive strain of cervical cancer took her life in 1951, when she was only 31. But cells harvested from her tumor, without her consent, have lived on ... and on and on.

The best-selling book The Immortal Life of Henrietta Lacks, which features the striking image of Lacks on its cover, tells the story of this African-American woman, her family, and her fast-growing cells, used in over 70,000 medical studies.

"HeLa cells," as they are called, have made vital contributions to the development of drugs for herpes, leukemia, influenza, and Parkinson's disease. The cells have been used in studies on everything from lactose digestion to mosquito mating. "The cells reproduced an entire generation every twenty-four hours, and they never stopped,"