This book constitutes the proceedings of the Fourth International IFIP Working Conference on Enterprise Interoperability (IWEI 2012) , held in Harbin, China, September 6-7, 2012. The theme for IWEI 2012 was "Collaboration, Interoperability and Services for Networked Enterprises", so submissions and discussions focused on these three areas critical for enterprise interoperability.The 10 full papers, 3 short papers, and 4 invited papers presented in this volume were carefully selected from 21 submissions, following a thorough reviewing process, during which each paper was scrutinized by at least three experts in the field. The papers cover a wide spectrum of enterprise interoperability issues, ranging from foundational theories, frameworks, architectures, methods and guidelines to applications, and case studies. In addition, this volume also includes the two invited keynotes.The 10 full papers, 3 short papers, and 4 invited papers presented in this volume were carefully selected from 21 submissions, following a thorough reviewing process, during which each paper was scrutinized by at least three experts in the field. The papers cover a wide spectrum of enterprise interoperability issues, ranging from foundational theories, frameworks, architectures, methods and guidelines to applications, and case studies. In addition, this volume also includes the two invited keynotes.