Henk Barendregt is a Dutch mathematician and computer scientist known for his work in the fields of logic, type theory, and the foundations of mathematics. He has made significant contributions to the development of the lambda calculus, a formal system in mathematical logic and computer science that is essential for understanding computation. Barendregt has also been involved in research related to proof theory and functional programming. His work has influenced various areas, including artificial intelligence and programming languages, making him a prominent figure in the study of theoretical computer science.