This booklet is the result of work by the European Federation of National Maintenance Societies (EFNMS), a non-profit organisation created in 1970. It brings together the National Maintenance Societies (NMS) of 24 European countries, with the aim of sharing experiences and collaborating to develop the maintenance profession and create a European maintenance culture. EFNMS carries out various activities to achieve these objectives, including leading six committees focused on key areas of maintenance: asset management, certification of personnel, training, health & safety & environment, maintenance indicators and assessment, and digitisation and new technologies. Additionally, every two years, in partnership with a selected NMS, EFNMS organizes the Euromaintenance conference, attracting experts and companies from around the world. Together, these activities aim to collect and develop maintenance knowledge to increase the visibility of this field and its professions, thus playing an essential role in the sustainable development of our industries and economies. To further enhance its work, EFNMS has decided to create a Maintenance Body of Knowledge (BoK). The objective of the BoK is to define the landscape, scope, boundaries, and content of maintenance to foster a better understanding of this area and highlight its importance within organisations. The BoK is based on European maintenance standards, actively contributed to by EFNMS, particularly the terminology and standards that describe the maintenance process and its relationship with asset management. The BoK is constructed upon these standards; it combines the maintenance actions and the knowledge necessary to carry them out (industrial issues, methods, techniques, practices, etc.). It serves as a catalog of maintenance knowledge, compiled from Euromaintenance conferences, the European standard on the qualification of maintenance personnel, various works of the EFNMS committees, and expert opinions. The texts were written by European experts and validated by the EFNMS Reading Committee. They provide short summaries of the subjects and include bibliographies that allow readers to access more detailed information. The links to the maintenance processes are indicated, enabling better identification of the competences expected from technicians, engineers, maintenance managers, and asset managers.

This BoK is a collaborative document intended to be regularly supplemented, updated, and improved by any expert in a particular area who wishes to propose changes, under the supervision of the Reading Committee. The goal is to create a dynamic reference that clearly explains the content of maintenance and its relationship with other processes within companies or organisations, thus contributing to the development of maintenance for the benefit of European and global populations. Readers are invited to communicate their points of view, clarify descriptions, and correct or supplement subjects with the intention of developing the culture of maintenance.