Marguerite Perey is best known for her discovery of francium, the 87th element in the Periodic Table. Francium, a rare, highly unstable, radioactive element, is the heaviest chemical of the alkali metal group. Perey's work on francium and on such scientific occurrences as the actinium radioactive decay series led to her admission to the French Academy of Sciences. Perey was the first woman to be admitted to the two-hundred-year-old Academy--even Marie Curie had been unable to break the sex barrier.

Marguerite Catherine Perey was born in Villemomble, France, in 1909. As a child, she showed an interest in science and wanted to become a doctor. Her father's early death, however, left her family without the resources for such an education. Nonetheless, Perey was able to study physics and showed a talent for scientific endeavors. Because of her technical prowess, she was able to secure a position as a lab...