Henrietta was a poor black woman living outside Baltimore at the time she discovered she had terminal cancer in 1951. When one of her doctors was able to keep her cancer cells (now known as HeLa cells) alive and growing indefinitely in the laboratory, it was one of the most important discoveries of modern oncology. But who was this woman who had unknowingly contributed so much to science at the moment of her death? Skloot expertly uncovers the mystery of the face behind the cells.