“The truth is what matters,” wrote James Frey in “A Million Little Pieces,” his 2003 memoir of addiction and recovery. “It is what I should be remembered by, if I am remembered at all. Remember the truth. It is all that matters.” But this week, Mr. Frey’s praise of the truth, along with many other passages in his bestselling, Oprah Winfrey-endorsed book, is starting to ring hollow.

On Monday, the Smoking Gun Web site published a lengthy investigation of “A Million Little Pieces,” presenting seemingly conclusive evidence that some of the most memorable episodes in Mr. Frey’s alleged autobiography were grossly exaggerated, or invented out of whole cloth. Within hours, the Internet was ablaze with speculation and schadenfreude about the bellicose Mr. Frey, who once notoriously declared, “I’m going to try to write the best book of my generation and I’m going to try to be the best writer.”

But as the scandal continues to spread, the most important question about Mr. Frey’s memoir has yet to be asked. Did “A Million Little Pieces” ever seem true in the first place?

“A Million Little Pieces” has been acclaimed for its gripping realism, but it seems real to so many people only because it is written according to a readily understandable, widely accepted code of realism. Its plot and character conventions come from movies and television (not surprisingly, before he published his first book, Mr. Frey was a Hollywood screenwriter). And its language is no less conventional: a debased macho naturalism learned from Hemingway and Kerouac, in which long paratactic sentences stand for objectivity, and muted sentimentality stands for masculine reserve. Few books are so patently artificial, so obviously made – and the Latin word for making is what gives us our own word “fiction.”

Why, then, if Mr. Frey’s book is clearly fictive, should we be surprised to learn that it is partly fictional? In fact, the source of the current confusion about “A Million Little Pieces” is not simply Mr. Frey’s dishonesty, but our mistrust and misunderstanding of fiction as a genre. Once, young writers aspired to write novels, and many first novels ended up reading like thinly disguised memoirs. Now, young writers aim to break into the marketplace with quirky or pitiful memoirs, hoping to follow in the footsteps of best sellers like David Sedaris and Haven Kimmel.

Despite the old adage “write what you know,” however, writing truthfully is not the first thing a writer learns to do, but one of the last; so these memoirs inevitably bear the patterns and shapes, the gratifying received formulas, of fiction. Only once the label of “memoir” or “nonfiction” is slapped on such a narrative does their literary artificiality start to look like an ethical trespass, rather than what it is: an aesthetic failure, a case of impoverished imagination.

The investigation that touched off the Frey affair was concerned with only a few episodes in “A Million Little Pieces,” which purports to tell the true story of the author’s treatment for alcoholism and drug addiction at the Hazelden Clinic in the early 1990s. Throughout the book, Mr. Frey repeatedly declares, with a typical combination of guilt and bravado, “I am an Alcoholic and I am a drug Addict and I am a Criminal.”

Naturally, most of what happened to Mr. Frey in rehab cannot be fact-checked, and most of the people he befriended are said to have died before his memoir was published. But Mr. Frey’s identity as a “criminal” should have left some public records, and it was the absence of these that made the Smoking Gun editors suspicious. What began as an attempt to locate Mr. Frey’s mug shot, for the Web site’s collection of celebrity jailhouse photos, eventually turned up convincing evidence that several episodes in “A Million Little Pieces” never took place in anything like the form Mr. Frey claimed.

By exposing some exaggerations in Mr. Frey’s book, the Smoking Gun investigation opens up the larger question of its emotional and literary falsehood. Mr. Frey’s claim to be writing the truth is central to his book’s huge success, and it is the sole reason why “A Million Little Pieces” was chosen by Oprah as required reading for her millions of viewers. But in fact, in recounting his story of despair and salvation, Mr. Frey draws on one of the oldest, most potent narratives in American culture. Addiction and recovery is the contemporary secular version of the old religious trope of sin and redemption, which has always had a double appeal: The allegiance to sanctity licenses the detailed description of profanity.

To say Mr. Frey’s tale makes use of an old trope, a conventional form, is to say it bends experience to certain predetermined patterns. Any reader who approaches “A Million Little Pieces” with ordinary wariness will spot such patterns – not to say stereotypes – behind nearly every one of the book’s anecdotes and characters. Lilly, the fellow patient whose love redeems Mr. Frey – and whose suicide is described in his 2005 sequel, “My Friend Leonard” – is that hoary cliche, the prostitute with a heart of gold. Leonard, the avuncular mobster who treats Mr. Frey as a surrogate son, is another cliche, straight out of “The Godfather” or “The Sopranos”; so is the abusive priest who gropes Mr. Frey, murmuring “you must not resist God’s will, my Son.” Many of the book’s most graphic scenes have immediately recognizable pop-culture sources: The episode in which Mr. Frey undergoes a root canal without anesthesia, for instance, comes straight out of “Marathon Man.”

It is too soon to say whether “A Million Little Pieces” will suffer permanently, in sales or reputation, from the current imbroglio. But it is only fair to acknowledge that Mr. Frey has simply given the literary marketplace what it so eagerly demanded: a brand of memoir that bears the same relation to experience as reality television does to reality.