Krzysztof R. Apt (born 26 December 1949 in Katowice, Poland) is a Polish computer scientist. He defended his PhD in mathematical logic in Warsaw, Poland in 1974.[1] His research interests include program correctness and semantics, use of logic as a programming language, distributed computing, and game theory. Besides his own research, he has been heavily involved in service to the computing community, notably by promoting the use of logic in computer science (in particular by founding a new journal) and by advocating open access to scientific literature.