Once known for gentle cheerleading and encouragement, the genre now berates readers with 'you're an idiot' messages.

Of all the aisles in the typical American bookstore, none has expanded faster than the one devoted to self-help. But customers looking for some sage words of relationship advice or a little "you can do it!" encouragement to lose weight may be in for a shock. The motivational gurus of the Simon Cowell (of "American Idol" fame) generation are here with blunt appraisals of our personal shortcomings.

Pointed and politically incorrect titles like "He's Just Not That Into You" and "Skinny Bitch" are burning up bestseller lists and inspiring copycats. The latter, written by former model Kim Barnouin and modeling agent Rory Freedman, is now No. 1 in paperback advice books on The New York Times bestseller list. A cookbook sequel came out in December.

Experts say their popularity re­­flects a demand from young, mainly female readers for in-your-face entertainment mixed with advice. While some say this new writing style may work where traditional prose or experts have failed, others question whether this trend degrades the reader and reflects poorly on our self-centered society.

"There's this new breed of self-help book," says Terrence Real, a bestselling self-help speaker and author of "The New Rules of Marriage." "They have a very black-and-white message that appeals to some people. Whatever the overt message is, the under­­lying message is, 'You're an idiot.'"

The new cookbook by Ms. Barnouin and Ms. Freedman pro­­motes a vegan diet. A sassy illustra­tion of an angular woman in a chic cocktail dress on the cover and advice such as "Stop being a moron and start getting skinny" hint at the vulgarity-laden blunt talk found inside.

Their first book didn't get much traction, selling only 10,000 copies when it debuted in 2005. But in May 2007, when the lithe Victoria Beckham was photographed holding up a copy in a Los Angeles store (despite the fact that she didn't buy it and says "I've never read a book in my life"), sales soared.

This nontraditional approach and vernacular voice also permeate "He's Just Not That Into You: The No-Excuses Truth to Understanding Guys." While relationship books of the past featured hints on how to attract "the man of your dreams," this book - which sold 30,000 copies in the first two weeks after its release in 2004 - tells women that if a guy doesn't call or ask them out right away, he's not interested, and they should give up.

The book's title - from a line of dialogue in a "Sex and the City" episode - has become such a catchphrase that it's being turned into a major film starring Ben Affleck and Jennifer Aniston. Meanwhile, the success of Freedman and Barnouin's books have prompted them to begin work on another, this one for pregnant women.

The new, no-holds-barred world of self-help also includes "Why You're Still Single: Things Your Friends Would Tell You If You Promised Not to Get Mad" (May 2006) and "You're Fat! Now Lose It!" (September 2007).

A desire to improve and achieve goals is part of American character and history, says John Hinds, an author and reviewer of hundreds of self-help products. The trend started in the 18th century, when self-improvement tips began to appear in booklets and newspapers.

Self-help book sales quadruple

Today, although book sales are down overall, self-help books continue to expand a multibillion-dollar market. Almost half of Americans purchase at least one self-help book in their lifetimes. The genre accounted for $581 million in sales in 1998, but today that number has quadrupled to more than $2 billion.

It's not surprising that self-help has moved to the small screen, finding ratings success with shows like "Dr. Phil," which premièred in 2002. The Oprah Winfrey-promoted psychologist doesn't mince words when it comes to berating his guests for their choices and telling them to change.

"It's somewhere between a serious psychological show and 'Jerry Springer,'" Mr. Real says. It was only a matter of time, he says, before the book industry picked up on this penchant for punishment.

Theories abound as to why self-help has taken this turn and what it says about contemporary US society - particularly women, who are the primary audience for such books.

Americans who pick up books these days often expect to be entertained, experts say. And an irreverent tone is not only entertaining, but also appeals to young people tired of politically correct prose.

"Sometimes 'harsher' is perceived as 'more expert,'" critic Real adds.

"There's so much soft-pedaled research out there," says Jennifer Kasius, executive editor at Running Press, publisher of Freedman and Barnouin's books, "like this or that may be good for you - we don't know what to do. It's refreshing for someone to come out and say, 'No, shut everything else out and listen to me.'"

Besides the surface appeal of the tone, the underlying message seems to jibe with how pop culture portrays women.

Self-help books reflect culture

"Self-help books reflect whatever the prevalent ethic of the culture is," says Wendy Kaminer, the feminist author of "I'm Dysfunctional, You're Dysfunctional," a critique of the self-help movement. "This is how a particular group of women sees itself." Bombarded with media messages that demand physical perfection, many women feel guilty about their weight or relationships. Instead of being put off by a self-help author's insults, these women are drawn to it as the kick they need to achieve their goals.

These books address modern women who find themselves competing with men in the workplace, but still facing - and sometimes embracing - a sexualized, traditional view of female worth and power, Ms. Kaminer says. This tough-love movement also follows the trend of groundbreaking self-help books appearing in worrisome times. For both men and women, "We desire certainty in uncertain times," says Real.

This is an age of "new insecurity" in American life, says Micki McGee, author of "Self Help, Inc.: Makeover Culture in American Life." With divorce and competition for jobs more prevalent than ever, Americans can't just maintain their appearance or job skills, they must constantly improve them. "For all our claims to egalitarianism, we live in a society where we see ourselves as competitors - for jobs and for affection," Ms. McGee says.