This book is the final report of the xAF (Extensible Architecture Frameworks) working group of the NAF (Netherlands Architecture Forum).

A new discipline, called Enterprise Engineering, is emerging. The mission of Enterprise Engineering is to combine (relevant parts from) the traditional organizational sciences and the information systems sciences, and to develop emerging theories and associated methodologies for the analysis, design, engineering, and implementation of future enterprises. Two fundamental notions have already proven to be indispensable for accomplishing this mission: Enterprise Ontology and Enterprise Architecture.