Admiralty printed books and pamphlets issued to the Navy in the BR (Books of Reference) series, which did not need inclusion in the security classified CB or SP series. They include regulations and instructions, handbooks and training manuals, reports and works of reference.
The subjects dealt with by BRs include almost all those about which officers, ratings or civilian employees might need to be informed, which were insufficiently secret to be issued as CBs. They include all sorts of regulations and instructions, handbooks of weapons and equipment, training manuals, works of reference, historical studies (including the Naval Staff "Battle Summaries"), reports and studies of damage to ships in action, and the Geographical Handbooks produced by the Naval Intelligence Division. The series also includes some of the similar works produced by the same Division's Interservice Topographical Information Centre for the use of all services.