Brian Greene is an American theoretical physicist, mathematician, and string theorist. He is known for his groundbreaking work in superstring theory, which seeks to unify the fundamental forces of nature. He is the author of several popular science books, including The Elegant Universe and The Fabric of the Cosmos. He is also the co-founder of the World Science Festival, an annual event that celebrates science and its impact on society. Greene is a professor of physics and mathematics at Columbia University and a member of the National Academy of Sciences. He has received numerous awards and honors for his work, including the National Medal of Science and the Special Fundamental Physics Prize.