The mathematician William James died at the age of 46. Here is all you want to know, and more!
Biography - A Short Wiki
Best remembered as a child mathematical prodigy, this New York man began attending Harvard University when he was just eleven years old. After teaching briefly at Rice University and being arrested for his participation in a 1919 socialist demonstration, he largely sank into obscurity.
He and his sister were born in New York City to a family of Ukrainian-Jewish immigrants; their father was a prominent psychiatrist, and their mother was a physician. He died in his forties from a cerebral hemorrhage, the same medical event that had killed his father.