This book constitutes the thoroughly refereed proceedings of the 14th International Conference on Theorem Proving in Higher Order Logics, TPHOLs 2001, held in Edinburgh, Scotlang, UK in September 2001. The 23 revised full papers presented together with one invited paper and two invited abstracts were carefully reviewed and selected from a total of 47 submissions. All current issues in HOL theorem proving and formal verification of hardware and software systems are addressed. Among the HOL theorem proving systems evaluated are Coq, HOL, Isabelle, and PVS.