Socks User Manual
The "Socks User Manual" is, as its name says, a user manual for the complicated contraption that is the sock.
It comes with helpful illustrations of socks, their measurements and component descriptions, as well as useful examples of things that are not socks, which include, among others, the following:
Such books are popular among Three-eyed Gelatinous Slime-Monsters, who deal in left sock gathering and may often have some difficulties telling Not Socks apart from Socks. When Not Socks are found in Left Sock Storage Depots and lie about being Socks, they will usually be taken to the Detention Centre, as happened in Comic 151.