Marie Skłodowska Curie was a Polish-French physicist and chemist who discovered radioactivity and the methods used to isolate radioactive isotopes. She and her husband were jointly awarded the Nobel Prize in Physics in 1903, and she received a Nobel Prize in Chemistry in 1911.
It is unfortunate, then, that what killed Curie was the very thing that she devoted her life to. She suffered many ailments due to exposure from radiation, including cataracts that rendered her nearly-blind. In 1934, she died from aplastic anemia, a rare bone marrow disease caused by radiation.