If one absence catches the eye in almost all literature about (re)designing or (re)engineering of enterprises, it is the lack of a well-founded theory about their construction and operation. Often even the most basic notions like "action" or "process" are not precisely defined. This book offers a theory and a matching methodology which has passed the test of practical experience. The enterprise ontology developed by Dietz is the starting point for a practical course of change that addresses numerous issues in an integrated way: business processes, in- and outsourcing, information systems, management control, staffing etc. Researchers and students, managers, and business analysts will discover in this book a revolutionary new way of thinking about business and organization.