There have been two famous Dr. Paul Ehrlichs
An American, Paul R. Ehrlich (1932-), is a Stanford University professor and a renowned entomologist specializing in Lepidoptera (butterflies). He is the author of The Population Bomb and other books which apply the lessons of population zoology to economic issues such as resource use and population growth. His predicitions of massive global starvation and resource depletion have so far proven wrong. Participant in a famous wager with Julian Simon, see Julian Simon/Wager.
A German, Paul Ehrlich (1854-1915), won the 1908 Nobel Prize in physiology or medicine. He is noted for his work in hematology, immunology, and chemotherapy. His life is depicted in the movie The Magic Bullet, which focused on his cure for syphilis. His biography is available at:
Nobel Museum Site]