Andrej Bauer is a professor of computational mathematics at the Faculty of Mathematics and Physics, University of Ljubljana. His research spans foundations of mathematics, constructive and computable mathematics, type theory, homotopy type theory, and principles of programming languages. With Matija Pretnar he designed the programming language Eff, the first language to support first-class algebraic effects and handlers. He was a member of the team of mathematicians who developed homotopy type theory at the Institute for Advanced Study. His latest research aims to provide a general mathematical understanding of what type theories are, and how we may implement them in practice, even when they lack good computational properties.