This edited volume of articles provides a state of the art description of research in logic based approaches to knowledge representation which combines approaches to reasoning with incomplete information that include partial, modal, and nonmonotonic logics. The collection contains two parts: foundations and case studies. The foundations section provides a general overview of partiality, multivalued logics, use of modal logic to model partiality and resource-limited inference, and an integration of partial and modal logics. The case studies section provides specific studies of issues raised in the foundations section. Several of the case studies integrate modal and partial modal logics with nonmonotonic logics. Both theoretical and practical aspects of such integration are considered. Knowledge representation issues such as default reasoning, theories of action and change, reason maintenance, awareness, and automation of nonmonotonic reasoning are covered.