Who has won the Nobel Prize in the same category twice?
Frederick Sanger: Frederick Sanger ( ; 13 August 1918 – 19 November 2013) was a British biochemist who twice won the Nobel Prize in Chemistry, one of only two people to have done so in the same category (the other is John Bardeen in physics), the fourth person overall with , and the third person overall with two Nobel Prizes in the sciences. John Bardeen: John Bardeen ( ; May 23, 1908 – January 30, 1991) was an American physicist and electrical engineer, the only person to have won the Nobel Prize in Physics twice: first in 1956 with William Shockley and Walter Brattain for the invention of the transistor; and again in 1972 with Leon N Cooper and John Robert Schrieffer for a fundamental theory of conventional superconductivity known as the BCS theory.
who twice won the Nobel Prize in Chemistry, one of only two people to have done so in the same category (the other is John Bardeen in physics)