book titles
There is a tradition in hackerdom of informally tagging important textbooks and standards documents with the dominant color of their covers or with some other conspicuous feature of the cover. Many of these are described in this lexicon under their own entries. See Aluminum Book, Blue Book, Camel Book, Cinderella Book, Devil Book, Dragon Book, Green Book, Orange Book, Purple Book, Red Book, Silver Book, White Book, Wizard Book, Yellow Book, and bible; see also rainbow series. Since about 1983 this tradition has gotten a boost from the popular O'Reilly and Associates line of technical books, which usually feature some kind of exotic animal on the cover.