This document aims to improve the standard of operating and maintenance manuals available within the building services industry by providing a structured guide to their preparation. Lists the cost benefits resulting from a properly-prepared manual, and how they can be achieved. Divides the Guide into three parts - 1) Considers the content and format of O and M manuals, 2) Examines the conditions and procedures for obtaining manuals of a satisfactory standard, 3) Examines updating procedures and their importance. Four appendices treat 1) maintenance labour resource options, 2) a check list for building engineering services, 3) examples of the minimum requirements for plans and drawings in an O and M manual, 4) provides a list of specialist organisations for the preparation of O and M manuals.