The taste of the book-buying public changes so quickly that the commercial lives of writers ought to be measured in dog years. Best selling authors who stay popular for more than a decade, like Tom Clancy and Danielle Steel, are as exceptional in publishing as players like Cal Ripken Jr. are in baseball. It's remarkable when an author comes back with a best seller after a 12-year hiatus; it's even more remarkable that this sort of reception is given to a tale about a cave girl.

People certainly aren't buying Jean M. Auel's The Shelters of Stone (Crown, 720 pages, $28.95) because of the writing. It's dreadful. The dialogue is wooden, the descriptions bloated, and the plot moves with glacial slowness. As for the characterizations, they're as subtle as the judgments of middle school girls.

Here's the situation. Ayla (the new girl in Perigord High) has hooked up with Jondalar (a studly hunk who's really good in hunting, shop and bed).

That's made Marona (the platinum blond ex-girlfriend) jealous and mean.

Sometimes Ms. Zelandoni, the big old home economics teacher, gives Ayla a tough time but she thinks Ayla's really smart and hopes she'll decide to be a teacher some day. Ayla's built like Barbie. She has a cool dog and her own horse. She's really hot, but she's still nice to the loners and dorks. And everyone wants to copy her cool outfits.

It's not like her life's perfect. She's got this scar thing on her leg and doesn't know how to wear her hair. Sometimes creepy men leer at her and make nasty comments. She's an orphan too, and she's hiding a big secret -- back when she was living with a foster family of Neanderthals, she had a baby and had to give it up for adoption.

Now, Ayla's pregnant again. But that's OK because she and Jondalar are going to get married and his family's cool about the whole thing. She's not sure she wants to go into teaching, but she really likes taking care of people who are sick or hurt so maybe she could be a nurse or open a naturopathic pharmacy. Still, more than anything, she wants to settle down and start a family.

If the writing is bad, the plot plodding, and the characters silly, why are so many people enjoying this book? First, there's lots of interesting detail here about life in Ice Age Europe. And second, the concerns, emotions and motivations of Auel's characters are just like the concerns, emotions and motivations of people today.

Prehistoric, according to Auel, doesn't mean pre-human. The people in her books (leaving aside the Neanderthals, who I'll get to later) live in caves and use stone tools, but they still need to put food on the table and look after their homes and possessions. They care about how they look, struggle with cantankerous neighbors, and help folks in need. The setting may be exotic, but the people are no different from us.

Unfortunately, that nice sentiment is completely misguided. The people of the Upper Paleolithic (roughly 30,000 to 15,000 B.C.) were profoundly different from us in ways we can demonstrate, ways we can guess, and, presumably, in ways we can't even imagine.

First, the archaeological record shows that people of the era were incredibly conservative. The tools they used, foods they ate, and methods they used to prepare those foods altered less over the 15,000 years of the Upper Paleolithic than our own technology and subsistence have changed over the last 15. Remember when you first used a cell phone, drove a car with antilock brakes, or ate sushi? The only things the people of the Upper Paleolithic saw change were the seasons.

Second, they lived in very small groups that were scattered over very large territories. The caves and rock shelters of the Perigord region in south central France, where Auel sets this story, were never all occupied simultaneously. At the same time, individuals wouldn't have wandered off on thousand-mile journeys like the one Jondalar was on when he met Ayla. Their lives depended on the support of the others in their bands and on an intimate knowledge of the regional landscape.

Auel does get a lot of specifics right. Paleolithic peoples seem to have had shamans, like Ms. Zelandoni who wants Ayla to become her disciple. They painted the walls of caves, probably fermented mildly alcoholic drinks, and certainly ate any root, fruit or green they could find. And many of the specific objects she describes in her books actually exist, though the sites they came from sometimes have dates that are thousands of years apart.

But did people specialize in particular crafts, accumulate goods, and trade what they made? Almost certainly not. The hunters and gatherers known to anthropologists share things rather than trading them (it helps minimize conflicts), and they have no use for more stuff than they can carry. And unlike Ayla, people in the Ice Age probably only bathed if they slippcrossing a river.

How else might our ancestors have been different? Maybe they thought counting people was unlucky or cut scars in their faces to mourn the dead.

Maybe they saw constellations in the dark patches of the Milky Way, like the Incas in Peru. We don't know how they figured kinship or whether they spoke each other's names. Maybe they didn't even have names.

Yet Auel rarely lets the people of the Upper Paleolithic think like anything but modern-day Americans. She only gets imaginative when she describes the Neanderthals. These people, who Auel calls "the Clan," speak with hand signs and won't let women hunt. They share inherited memories and are not shy about public sex. They were far and away the most interesting characters in Auel's earlier books, and not a single one appears in this new volume.

So what should people who are curious about Stone Age societies be reading? For information on objects, their associations, and their chronology, archaeologists read site reports. I've been waiting for volume 3 of the Tell Brak Excavation Reports, for example, almost as long as Auel's fans waited for The Shelters of Stone. But nobody in their right mind reads site reports for fun.

I'm fascinated by ideas about the evolution of ancient societies as discussed in Uruk Mesopotamia & Its Neighbors (School of American Research Press, 584 pages, $24.95) edited by Mitchell Rothman and Bronze Age Economics (Westview Press, 432 pages, $42) by Timothy Earle. But the writing in both of these books is abstruse, technical and full of footnotes -- in a word, academic. It's not something most readers would enjoy.

Unfortunately, three of the best books about our Paleolithic predecessors are out of print. But your local library can certainly hunt up copies of The Neandertals: Of Skeletons, Scientists and Scandal (Vintage Books) by Erik Trinkaus and Pat Shipman, and two marvelous novels, Reindeer Moon (Pocket Books) and The Animal Wife (Pocket Books) by Elizabeth Marshall Thomas.

If you want a single recommendation, read Reindeer Moon. It is the most thoughtful, interesting and elegantly imagined account of Ice Age life that I have ever read.

John R. Alden is an anthropological archaeologist interested in the appearance and evolution of state-level societies. Although he has studied such societies for most of his career, his first archaeological experience, in 1969, was excavating a cave in the Andes occupied by pre-ceramic hunter-gatherers. He can make stone tools, but has never started a fire with anything but a match or a lighter.