Conditionals in Nonmonotonic Reasoning and Belief Revision : Considering Conditionals as Agents Conditionals are omnipresent in everyday life as well as in scientific environments; they represent generic knowledge acquired inductively or learned from books. They tie a flexible and highly interrelated network of connections along which reasoning is possible and which can be applied to different situations. Therefore conditionals are important but also quite problematic objects in knowledge representation.This book presents a new approach to conditionals which captures their dynamic non proportional nature particularly well by considering conditionals as agents shifting possible worlds in order to establish relationships and beliefs. This understanding of conditionals yields a rich theory which makes complex interactions between conditionals transparent and operational. Moreover it provides a unifying and enhanced framework for knowledge representation nonmonotonic reasoning belief revision and even for knowledge discovery