The National Science Foundation (NSF), which was created by the U.S. Congress in 1950, is currently the second largest U.S. government research-funding agency (next to the National Institutes of Health). The president appoints the NSF director and the 24 members of the National Science Board, which establishes the overall policies of the foundation. With an annual budget of approximately $7.5 billion, NSF funds about 24% of all federally supported basic research conducted by U.S. colleges and universities. It receives 50,000 proposals per year and annually supports 200,000 scientists, engineers, educators, and students in the United States and throughout the world. NSF is the major source of federal funding in the social sciences and in science education. This entry reviews the mission and organization of NSF, ...