This novel is most famous as a precocious debut novel (it came out when Ellis was 21 years old) and as a shocking social pathography, describing the moral and psychological vacuity of a generation lost in drugs and sex.  The characters barely stir from their spoiled, stoned lethargy, so apathetic and narcissistic it makes "ennui" seem positively romantic.  As a work of fictional documentary, it is a shocking portrayal of dissolute youth in the Reagan era, and certainly deserves to be catalogued in the canon of drugs literature: cocaine, marijuana, alcohol, heroin, qualudes, benzodiazapenes are readily sniffed, smoked, imbibed, injected, and swallowed.  Clay's friend Trent, a male model, is given the surname Burroughs in the sequel Imperial Bedroom - a reference perhaps to William Burroughs (likely not so much a reference to the voluptuous, slimy carnality of Naked Lunch as the bleak desperation of Junky).

As a social pathography, it can be tremendously funny: Clay can't really tell his sisters apart (a symptom not just of a distant family or a misogyny but of an essential interchangeability of people for Clay: people are their names and their immediate reactions, but not much else); Clay's psychiatrist is much more interested in becoming a screenwriter than helping his late-adolescent patient transition into adulthood.  This is the great, damning, controversial introduction to Generation X as callow, unfeeling youth searching out darker and darker thrills; to their parents, callow, unfeeling adults too blitzed to feel much of anything; and the shallow materialism of their world.  

In some ways the novel has become dated, but not always in expected ways.  The characters watch music videos on MTV and play early video games, which probably registered in the mid-1980s as another symptom of a zombified youth without culture; now we see MTV and those early arcade games as harbingers of a new aesthetic.  However much it appears to describe a specific time and a specific place, the novel remains shocking.  It's more than a documentary or a social pathography; it's a horror story.

Replete with references to werewolves and vampires, to serial killers and ghosts, Less Than Zero draws upon the images and tropes of the horror tradition to hone in on the great aesthetic tension: is it real or is it not?  Is it a documentary and a social pathography (is it real?) or are we just being pulled into a fictional world of monsters?  Usually, in the world of horror, attractive adolescents are the victims; in Less Than Zero, they're the monsters.  To be scared, to be startled requires an investment, a suspension of disbelief that says, at least for a moment, "I will believe this is real"; to laugh is to be amused at what ridiculous things you were willing to believe and be frightened by.  The "realism" of the novel, its documentary minimalism, is part of what makes the egregious excess so startling, and occasionally so funny.