SPOILER WARNING: Information after this point may spoil the OAV/OVA, TV series and/or manga.
The Gentleman Books was a project launched by the Special Operations Division to preserve Mr. Gentleman's knowledge. Seven books were made out of special paper, produced by Jiggy Stardust, and given to 7 different people in order to protect them for Mr. Gentleman's eventual revival. Alice Alice Arquette was given the master key.
The books have different names, depending on the translation: