– De Bruijn indices  still play an important role in the implementation of programming languages and theorem provers. – De Bruijn’s new type systems were influential in the discovery of new powerful type systems . – De Bruijn re-invented the Curry–Howard isomorphism (also referred to as the Curry–Howard–de Bruijn isomorphism). Independently of Curry and Feys  and Howard , we find a variant of the propositions as types principle in the first Automath system of de Bruijn (AUT-68 [12, 4]). Though de Bruijn was probably influenced by Heyting (see  in , p. 211), his ideas arose independently from Curry, Feys, and Howard, as can be clearly seen in Section 2.4 of , where propositions as types (or better: proofs as terms) are implemented in a way that differs from the method of Curry and Howard (see ). – The Landau book  on the foundations of analysis remains the only fully encoded and checked mathematical book in any theorem prover. The Landau book was encoded in Automath in the seventies by Bert van Benthem-Jutting (who was a Ph.D. student of de Bruijn at that time) [1, 2].