Julius Richard Büchi (1924–1984) was a Swiss logician and mathematician.

in 1950 at ETH Zurich under the supervision of Paul Bernays and Ferdinand Gonseth.

He and his first student Lawrence Landweber had a major influence on the development of theoretical computer science.

Together with his friend Saunders Mac Lane, a student of Paul Bernays as well, Büchi published numerous celebrated works.

He invented what is now known as the Büchi automaton, a finite-state machine accepting certain sets of infinite sequences of characters known as omega-regular languages.