The textbook includes the most important information for the operation of steam boiler systems in accordance with current legal requirements. In addition to the necessary chemical and physical fundamentals, it imparts knowledge about types of steam boilers, combustion systems, equipment, and auxiliary systems that are essential for understanding the function of steam boiler systems. Furthermore, operational aspects such as maintenance, typical malfunctions and damages, as well as legal requirements are presented comprehensively and practically. Alongside current technical and legal updates, each chapter also outlines the historical development, provided it is relevant for understanding the current information and existing systems. The book serves as a foundation for the training of specialized personnel who are employed in the use of steam boiler systems in industrial and utility companies. For operations managers, planners, installers, operational engineers, and those working as boiler attendants, the book is an important working resource and reference guide. As with the previous work, the established standard "Handbook of Boiler Operation Technology," the authors of the individual chapters are experienced experts from technical monitoring organizations. The new edition features an updated and condensed format that focuses on the most important information, creating a clear structure and overview.