There is an implicit code that customers rely on. If a book cover has raised lettering, metallic lettering, or raised metallic lettering, then it is telling the reader: Hello. I am an easy to read work on espionage, romance, a celebrity, and/or murder. To readers who do not care for such things, this lettering tells them: Hello. I am crap. Such books can use only glossy paper for the jacket; Serious Books can use glossy finish as well, but it is only Serious Books that are allowed to use matte finish.
Diminutely sized paperbacks, like serial romances or westerns or dieting and astrology guides, are aimed at the uneducated. But diminutely sized hardcover books are aimed at the educated – excepting those that are very diminutive, which are religious books aimed at the uneducated – and unless they are in a highly rectangular format, in which case they are point-of-purchase books aimed at the somewhat-but-not-entirely educated. However, vertically rectangular diminutive softcover books, which tend to be pocket travel guides, are aimed at the educated. But horizontally rectangular diminutive softcover books – a genre pioneered by Garfield Gains Weight – are not.
Then there are the colors. Bright colors, and shiny colors, are necessary for the aforementioned books with raised lettering. Black will work too, but only if used to set off the bright and shiny colors. Because, remember, with the customer base in mind, the book will need to be a bright and shiny object. Conversely, a work of Serious Literature will have muted, tea-stained colors. Black is okay here too, but only if used to accentuate cool blues and grays and greens.
Finally, on Serious Books and crap alike there will be a head shot of the Author sitting still while looking pensive or smiling faintly into the indeterminate distance – the one pose that has no existence in the author’s actual daily life. The size of this photo will be in inverse proportion to the quality of the book. If this photo is rendered in color, it is not a Serious Book. If there is no author photo at all, then it is a Serious Book indeed – perhaps even a textbook.
If a color photo of the author occupies the entire front cover, the book is unequivocal crap.