The reasons why readers devour mass pop fiction are far murkier than the counterplots and suspense devices that often drive them. To discriminating readers, more than half of most fiction bestseller lists are indigestible dreck. Grasping for understanding, from time to time I read a random example of brand-name commercial fiction. My latest test drive is Deadly Embrace, by Jackie Collins (Simon & Schuster, 517 pages, $26).

It begins on July 10, 2001, in Los Angeles, where the reader meets Madison Castelli, who has just flown in from New York. She is 30 and lovely, with emphatic mammary endowment and green almond-shaped eyes. She is a writer for a rich-and-famous magazine, looking forward to meeting her closest friends to talk about her woes.

What woes! On the first page, Collins writes:

"Her father, Michael, was being accused of a double murder. His estranged wife, Stella (Madison's stepmother), and Stella's live-in lover had been shot, execution style. Now there was a warrant out for Michael's arrest, and he'd managed mysteriously to vanish. ... Her boyfriend, Jake, was also on the missing list." She meets her pals at a restaurant, which immediately is raided by three drugged-up gunmen who shoot one diner dead, take the rest hostage and ... Well, all that's happened by the seventh of 517 pages. Enough to make a 30-year-old get mad -- or anyway nervous.

All the women in the book, with a couple of recondite exceptions, have sensuous lips and splendiferous upper-torso proportions. The men, too, are anatomical divinities. The whole book is told in short, staccato, declarative sentences, one-to-eight-line paragraphs. Like this:

"He'd killed a man in cold blood. It didn't seem real to him, and yet he's done it. And he would do it again if he had to.

"For his mother.

"For the woman he'd never met.

"For her honor."

The book is written in a series of vignettes, short scenes that come sometimes as quickly as flicks and flashes. The main characters are second-generation New York Italian-Americans and -- in one important case -- a faux-Mormon, incestuous multiple-mate ranch in rural Nevada. The main locus of the story is Las Vegas, though New York and L.A. play important scene-roles.

There are four or five separate stories, spanning the period from 1945 to last summer. By the end, all of the action gets tied up to make a whole.

Trademark Success

Going to shops this week, Deadly Embrace will sell in immense numbers. It's Collins' 21st book. All but the very earliest ones have been major best sellers. She was born Jacqueline Jill Collins in London 60-some years ago -- reports vary. Her sister Joan is the actress. She has been married twice, and widowed in 1992, and now lives in Los Angeles. It is estimated that her previous books have sold 200 million copies worldwide, including translations into 40 languages.

She has been called any number of things, pejorative and praiseful. But none quite so catchy as "the queen of trash-and-flash romance." She has often said that she takes elaborate guidance from the confided life experiences of her closest friends -- mostly Hollywood figurines -- for the anecdotal material of her books.

So why, oh, why, do millions of people leap to buy each one?

The level of casual sexual vulgarity struck me as astonishing. It is, anyway, unrelenting. Sex pervades almost every human contact and page of the book - alternating, or in counterpoint, with violence. All the separate groups of people become, in one way or another, intimately intertwined by couplings (or treblings, and so on), violence or greed -- sometimes even marriage. The vocabulary they use, and much of what they do, makes a rough episode of The Sopranos look a bit like a Sunday-school social.

But narratives of wide-open pornography are available everywhere -- at least in the U.S. -- and little or none of it sells at astronomical levels. So that's not it.

The people, maybe?

Characterization, complexity, insight, growth are not strong suits here. From childhood to, in some cases, old age, people remain nigh on identical. And their minds are hardly rich with insight.

Deep thoughts

For example, at one point, almost 15 years before the book's opening passages, Michael Castelli is flying from New York to Miami with his daughter -- you know, Madison -- who's thinking about graduating from her boarding school and going to college.

"He picked up a Time magazine and began reading. Madison gazed out the window, imagining herself as a published author along the lines of a Tom Wolfe or a Mario Puzo. She loved their books. The Godfather was her all-time favorite, and she'd just finished reading The Bonfire of the Vanities, which she'd devoured over two nights. Then again she wouldn't mind being a journalist -- covering wars and world events.

"I can do anything, she told herself. Anything I set my mind to."

That's as deep as it gets -- and as literary.

Having carefully navigated all 517 pages, I can say with conviction that it's all froth. Trivial -- but rollicking -- reading. Literary potato chips.

Underlying everything are human relationships -- all of them flawed or faulted. Almost no one is the product of a real, intact family. They were children of unexpected or unintended pregnancies, of hideously unloving or cruelly broken marriages.

Throughout, there is an essential aloneness. Loneliness and pain drive the narrative. Yet none of the characters is engaging enough to make one really give a much of a damn.

So, I believe, an answer to the puzzle lies in schadenfreude --that marvelous German word that means malicious joy provided by the misery of others.

Collins' characters suffer, all book long. What reader could fail to offer silent prayers of thanksgiving for being spared such woes? And then to rush out for the next fix.