Soy shakes, golden retrievers, squat thrusts. These aren't the makings of a week-long bender in Vegas, unless you happen to be Marquis de Sade. However, the human brain is a mysterious lump of meat, and under rare circumstances the mind can become hooked on all sorts of things that are usually completely innocent or even commendable.
Such as ...
Doesn't sound so bad ...
Many of us own collections that we're too ashamed to discuss in public, whether it's vintage porn, yarn or commemorative Burger King glasses. So when you hear there's such a thing as book addiction, you figure, hell, it'd be rad to be addicted to the Western literary canon. You'd be so quick with quips and quotes at dinner parties you could wear a damned monocle and nobody would dare call you on it.
The horrifying reality:
The most prominent modern bibiliomaniac was Stephen Carrie Blumberg. From 1974 to 1990, this bookish chap raided the archives of about 185 North American universities. When the FBI finally raided his Ottumwa, Iowa home, the feds discovered 28,000 stolen books and manuscripts he had been compulsively hoarding.
Bibliomaniacs like him don't necessarily read their books or even collect valuable ones. They just collect them out of a compulsive need to have a fuckload of books. So you could be a bibliomaniac while remaining completely illiterate, though you could build a kick-ass fort.
By the way, after Blumberg spent 4.5 years in prison for stealing all those books, he was rearrested in July 2003 for stealing, um, doorknobs. Figure that one out.
Technology has obviously made books unnecessary, so the sight of even one book in a friend's home should be cause for concern. If the person has gone as far as to purchase an entire special shelf to hold all of his books, it's probably time for an intervention.