Perry Orson Crawford, Jr. (August 9, 1917 – December 13, 2006) was an American computer pioneer credited as being the first to fully realize and promote the value of digital, as opposed to analog, computers for real-time applications. This was in 1945 while advising Jay Forrester in developing flight simulators and anti-aircraft fire control devices during World War II, before practical digital computers had been produced. His similar foresight on related issues led to his heading twelve years later the design team for IBM's SABRE project, the ticketing system for American Airlines, the first large-scale commercial application of real-time computer systems, which became the model for on-line transaction processing.