Book of SecretsBook of Secrets Assemble me. Discover my secret before entrusting me with yours! Lock your secret notes, precious treasures, or other personal items inside the Book of Secrets from Ugears and keep them safe from curious eyes. Books have been used to hide items, in real life and in fiction, for almost as long as there have been books. Homeowners can conceal valuables from burglars by hollowing out a book and placing it on a bookshelf with other tomes.