ThisvolumecontainsthepaperspresentedattheTenthInternationalConference on Logic for Programming, Arti?cial Intelligence, and Reasoning (LPAR 2003), heldonSeptember22 26,2003, inAlmaty, Kazakhstan, togetherwiththeFourth International Workshop on Implementation of Logics. There were 65 submissions, of which 8 belonged to the special submission category of experimental papers, intended to describe implementations or c- parisons of systems, or experiments with systems. Each submission was reviewed by at least three program committee members and an electronic program c-...