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- mitteemeetingwasheldviatheInternet.Weareverygratefultothe32program committee members for their e?orts and for the quality of their reviews and d- cussions. Finally, the committee decided to accept 27 papers. The program also included ?ve invited talks, by Franz Baader, Serikzhan Badaev, Dexter Kozen, Sergei Goncharov, and Thomas Wilke. Apart from the program committee, we would also like to thank the other people who have made LPAR 2003 possible: the external reviewers and the local organizers Serikzhan Badaev and Anna Romina. The Internet-based submission software and the program-committee disc- sion software were provided by the second co-cha

Reasoning about knowledge--particularly the knowledge of agents who reason about the world and each other's knowledge--was once the exclusive province of philosophers and puzzle solvers. More recently, this type of reasoning has been shown to play a key role in a surprising number of contexts, from understanding conversations to the analysis of distributed computer algorithms.Reasoning About Knowledge is the first book to provide a general discussion of approaches to reasoning about knowledge and its applications to distributed systems, artificial intelligence, and game theory. It brings eight years of work by the authors into a cohesive framework for understanding and analyzing reasoning about knowledge that is intuitive, mathematically well founded, useful in practice, and widely applicable. The book is almost completely self-contained and should be accessible to readers in a variety of disciplines, including computer science, artificial intelligence, linguistics, philosophy, cognitive science, and game theory. Each chapter includes exercises and bibliographic notes.