Barbara Liskov (1939 - ) is an American computer scientist who won a Turing award in 2008 and developed the Liskov substitution principle. After earning her BA in mathematics at UC Berkeley in 1961 she went on to become one of the first women to receive a Ph.D. in computer science, from Stanford University. Her thesis was a computer program to play chess endgames. She then moved to Boston to work at the Mitre Corporation in Bedford, MA on computer design and operating systems, and creating the Venus Computer. She left Mitre for a professor position at MIT, where she focused her research on creating more reliable computer systems, designing and implementing CLU programming language, and then creating the Argus language. In the 1980s, she became interested in using the internet as a tool: she has since focused largely on distributed systems, which use several computers connected by a network. Together with Jeannette Wing, she developed the Liskov substitution principle, a new notion of subtyping. Liskov has been focusing in recent years on cyber security and protecting data.