Scan the shelves of any bookstore and you'll find book jackets adorned with breathless endorsements such as these - all taken from actual covers - aimed at nudging the casual browser to pick up a book and feel good about buying it.

These quotes are called "blurbs," and to the publishing industry they're the equivalent of a Roger Ebert "Thumbs up!" on a movie poster. Authors like receiving blurbs because, well, everyone enjoys getting a compliment. Other writers - some of them, anyway - like giving blurbs because their name on book jackets helps promote their own work. Publishers like blurbs because the glowing quotes validate their publishing decisions and, presumably, boost book sales.

But how well do blurbs serve the reader? The answer is complicated.

"It's an odd game . . . sort of a sophisticated word of mouth," novelist and short-story writer Ron Carlson says about the arcane process of book blurbing. A Salt Lake City native, Carlson has blurbed his share of books and himself been blurbed by such big-name authors as John Irving. Unlike some other blurbers, he's measured in his compliments. "You don't call something a 'masterpiece' for two reasons. First, it is probably not a masterpiece, and second, it is of no help to a person standing in a bookstore about to choose [what to buy]."

Book blurbing is a relatively recent phenomenon. Thirty years ago, a hardback's rear cover usually featured a photo of the author and not much else. Nowadays that precious real estate, like every blank space inside most American sports arenas, has become a billboard. With paperbacks, an especially gushy or big-name blurb will even appear on the front cover.

Because book sales today are flatlining and hundreds of titles are competing for readers' attentions on bookstore display tables, publishers say they need every edge in promoting their authors.

"Book marketing is much more complicated and difficult than it was 30 years ago, partly because we publish so many books [and] partly because publicity opportunities are fewer," says Publishers Weekly editor-in-chief Sara Nelson, lamenting the demise of many newspapers' book sections. "So yes, I think blurbs are thought to be a way of getting a reader's interest. There's no exact study or way to determine how much blurbs influence sales, but it certainly is a topic of discussion in the publishing business."

The art of the blurb

What makes a great book blurb (other than the name, "J.K. Rowling" at the end of it)? That depends on the book's genre, of course, but observers agree it's more than just trotting out overused words such as "lyrical" or "riveting." Betsy Burton, owner of The King's English Bookshop in Salt Lake City, believes the best blurbs can express the soul of a book in a paragraph.

"There's an art to writing a blurb," she says. "To be able to convey in just a sentence or two what the book is about, so the reader has a real feeling for the guts of it . . . that's not easy."

Authors such as Sue Grafton or John Grisham are so famous they don't need blurbs. So publishers focus their blurb-harvesting efforts on lower-profile books, especially fiction, by lesser-known writers. After consulting with the author and his or her agent, editors typically mail advance editions of such books to established authors in the hopes of attracting a handful of blurbs they can then print on the hardcover. For subsequent paperback editions, it's often easier to cull blurbs from reviews in newspapers and magazines.

For his forthcoming book, Bargaining for Eden: The Fight for the Last Open Spaces in America, Salt Lake City writer Stephen Trimble gave his publisher a wish list of 20 people - including former vice president Al Gore - from whom to seek endorsements. When published in July, the dust jacket will bear six blurbs, including one from former Salt Lake City Mayor Rocky Anderson, who calls Trimble's book "a powerful call for us to more earnestly consider our solemn obligations as stewards of the Earth." (There's no blurb from Gore.)

Some reclusive authors, such as Cormac McCarthy, rarely if ever give blurbs. Others, such as Stephen King and Tony Hillerman, seem to lend their name everywhere. Industry observers warn that frequent or overpraising blurbers, sometimes known as "blurb whores," run the risk of of losing credibility with readers.

"If their name is on 50 books, their comments become less meaningful," says Kendra Harpster, an editor at Viking Penguin in New York. "How can every book be the greatest they've ever read?"

Carlson, whose recent novel Five Skies was blurbed by Rick Bass and Antonya Nelson, believes most authors are earnest in their praise of others' books. But that doesn't make it any easier to ask for blurbs.

"It's so awkward. I think all writers feel the same way," says the author, who teaches writing at the University of California at Irvine. "It's a little like asking for letters of recommendation. You hope people have time for it."

Carlson got an unlikely, and unsolicited, endorsement for A Kind of Flying, his 2003 story collection, when King, author of such horror classics as The Shining, discovered Carlson's work and sent a blurb saying, "These stories glow with a radioactive cleverness."

"He was very generous," Carlson says. "The day after that comment appeared . . . my stock went up with my students."

Blurb what you love

Authors who are solicited for blurbs say they try to strike a balance between blurbing too often and accommodating talented new writers who need exposure. Naturalist writer Terry Tempest Williams remembers how grateful she was as a fledgling author two decades ago when Jim Harrison and Wallace Stegner contributed blurbs for her book. Today, however, Williams blurbs just a fraction of the eight to 10 books sent to her each month.

"I only blurb books that I love," she says. "It's an issue of integrity. If you put your name down as an endorsement for a book, your readers trust you."

For less-established authors, however, it can be harder to say no.

"No one wants to have to write that e-mail that might dash someone's hopes, so sometimes it's just easier to write the blurb," says Sara Zarr, a Salt Lake City writer of young-adult novels. Of the 10 or so books she's read for possible blurbs, Zarr has endorsed just two. But she knows other writers who will write a blurb if they can find anything positive to say about the book. "Their blurb will focus on that one positive thing, ignoring the rest even if it's an absolute disaster."

At least those people presumably read the whole book they're blurbing. A personal assistant to one best-selling author, who asked to remain anonymous, says that because of time constraints, her boss usually just reads a chapter or two to "get a feel" for the book he's being asked to endorse. The assistant says that to save more time, she'll even sometimes ask a blurb-seeking author to write their own endorsement, which her boss then signs.

Like any industry, the literary world can be an incestuous place where agents, authors and editors do favors for one another. So can blurbs be trusted? Williams, who splits her time between Wyoming and southern Utah, thinks so.

"I've certainly blurbed friends' books, and they've blurbed mine," says the conservationist author of Refuge and Red: Passion and Patience in the Desert. "But it's never been the kind of thing where we say, 'OK, I'll do this for you if you do it for me.' "

"I don't think there's as much smoke being blown as you think," agrees Carlson. "The names on my books, they aren't people I knew [at the time]."

Observers suggest that readers learn to read between the lines of blurbs to determine whether an author genuinely loves the book. After all, a blurb such as "Nobody writes like Danielle Steel" can be taken several ways. Also, readers should pay attention to who's blurbing - if their favorite author likes a book, chances are they will, too.

"If it's a book I would read in the normal course of my life and want to recommend to all my friends, I'll write a blurb. If that recommendation would come with a dozen caveats, I decline," says Zarr, whose most recent book is Sweethearts. "Ultimately, the reading experience is so personal and subjective. You either respond to a book or you don't."

griggs@sltrib.com

Check your blurb-Q

A glowing book-jacket quote by a prominent author will brighten many a publisher's spirits. Can you match the blurb to the book?

1. "A terrifying and marvelous book." - Roald Dahl

2. "The agelessness of the human story as told by one of this century's most evocative writers." - Anne Tyler

3. "This is one of those unforgettable stories that stays with you for years." - Isabel Allende

4. "A book of the very first order, a superb book." - Saul Bellow

5. "A sobering and glorious book that you won't be able to put down." - Colin Powell

A. The Invisible Man, Ralph Ellison

B. Faith of My Fathers, John McCain

C. A Clockwork Orange, Anthony Burgess

D. Love in the Time of Cholera, Gabriel Garcia Marquez

E. The Kite Runner, Khaled Hosseini

BLURB QUIZ ANSWERS: 1= C, 2= D, 3= E, 4= A, 5= B

Helpful, or just billboards?

I only blurb books that I love. It's an issue of integrity. If you put your name down as an endorsement for a book, your readers trust you.

You don't call something a 'masterpiece' for two reasons. First, it is probably not a masterpiece, and second, it is of no help to a person standing in a bookstore about to choose [what to buy].

- Ron Carlson, whose recent novel Five Skies was blurbed by Rick Bass and Antonya Nelson.

No one wants to have to write that e-mail that might dash someone's hopes, so sometimes it's just easier to write the blurb.

- Sara Zarr, a Salt Lake City writer of young-adult novels.