1 Introduction.- 2 Consequence Relations.- 3 Epistemic States.- 4 Similarity and Decomposition.- 5 Epistemic Entrenchment.- 6 The Basic Inference Relation.- 7 Skeptical Inference Relations.- 8 Defeasible Entailment.- 9 Credulous Nonmonotonic Inference.- 10 Contraction Inference.- 11 Belief Change and Its Problems.- 12 Contractions of Epistemic States.- 13 Merge and Expansion.- 14 Compound and Derived Changes.- References.

This is the first book that integrates nonmonotonic reasoning and belief change into a single framework from an artificial intelligence logic point-of-view. The approach to both these subjects is based on a powerful notion of an epistemic state that subsumes both existing models for nonmonotonic inference and current models for belief change. Many results and constructions in the book are completely new and have not appeared earlier in the literature.