Customer orientation and professional service level management (SLM) are crucial for the long-term success of service companies. This book outlines the path to professionalizing the interface between service recipients and IT service providers. After an overview, the current standards for SLM (COBIT, ITIL, ISO 20000) and their application through case studies are described. Key focuses include practically applicable and robust service level agreements (SLAs), monitoring of business processes, and evidence of SLA compliance. The book presents working concepts and tools for service level managers, as well as pitfalls in service level agreements. The second edition has been completely revised and updated, particularly regarding IT standards, developments in the area of service catalogs, and a new penalty concept for damages.