Original: First synthesized in 1874 by Othmar Zeidler, DDT's insecticidal properties were not discovered until 1939 by the Swiss scientist Paul Hermann Müller, who was awarded the 1948 Nobel Prize in Physiology and Medicine for his efforts.
Simplified: The Swiss chemist Paul Hermann Müller was awarded the Nobel Prize in Medicine in 1948, for his discovery.NobelPrize.org: The Nobel Prize in Physiology or Medicine 1948 Accessed July 26, 2007.