Before revision: The Sagan Effect Pharmacologist Susan Greenfield has publicly discussed science-based social problems Carl Sagan was an accomplished researcher in the field of planetary science by the time he published his 1977 book The Dragons of Eden, on the evolution of human intelligence, targeted for general, non-scientific audiences.
After revision: The Sagan Effect Carl Sagan Carl Sagan was an accomplished researcher in the field of planetary science by the time he published his 1977 book The Dragons of Eden, on the evolution of human intelligence, targeted for general, non-scientific audiences.