Are you sure that the last page of the book doesn't have some instructions on who to contact in order to have the real book shipped to you? Maybe some twisted person(s) at O'Reilly thought it would be funny to sell a "gag book" per se, with the intention of later shipping them the real content? Or maybe they decided to save paper and you can read the real text by using a black light?

.oO( Did I get these ideas from a previous O'Reilly publication? "Publisher Crazy-Idea Handbook" or some such... )