Born in New York City in 1941, Stephen Jay Gould received his B.A. from Antioch College in New York in 1963. He received a Ph.D. in paleontology from Columbia University in 1967 and has been a professor at Harvard University since then. He is also curator of invertebrate paleontology at Harvards Museum of Comparative Zoology. His research has been mainly in the evolution and speciation of land snails. Gould is a leading proponent of the theory of punctuated equilibrium. This theory holds that few evolutionary changes occur among organisms over long periods of time, and then a brief period of rapid changes occurs before another long, stable period of equilibrium sets in. An outspoken advocate of the scientific outlook, Gould has been a vigorous defender of evolution against its creation-science opponents in popular magazines focusing on science. He writes a column for Natural History and has produced a remarkable series of books that display the excitement of science for the layperson.