This volume presents a variety of papers bearing on the relation between deontic logics, logics of action, and normative systems, i.e. systems of or about interacting agents (computers, human beings, corporations, etc.) whose behaviour is subject to ideal constraints that may not always be fulfilled in practice. The papers range from theoretical studies of the logical and conceptual tools needed, to studies of various applications. The set of papers collected in this book should be of interest to investigators working in a variety of fields, from philosophy, logic and legal theory to artificial intelligence, computer and management sciences, since it covers topics ranging from theoretical research on foundational issues in deontic and action logics, defeasible reasoning, decision theory, ethical theory, and legal theory, to research on a variety of issues relevant to applications connected with expert systems in the law, document specification, automation of defeasible reasoning, specification of responsibilities and powers in organizations, normative systems specification, confidentiality in database systems, and a host of other applications.