The Undecidable: Basic Papers on Undecidable Propositions, Unsolvable Problems, and Computable Functions: Dover Books on Mathematics

An anthology of fundamental papers on undecidability and unsolvability, this classic reference opens with Gödel's landmark 1931 paper demonstrating that systems of logic cannot admit proofs of all true assertions of arithmetic. Subsequent papers by Gödel, Church, Turing, and Post single out the class of recursive functions as computable by finite algorithms. 1965 edition.