He has a little trouble getting the word out, but when prompted, Joel Ralph readily confesses that he's obsessed.

The object of his compulsion is soft, lush, shapely — and green. Yes, Ralph's front lawn in Wynnewood, Pa., is a beauty, a symmetrical stretch of perfectly chiseled Bermuda grass overseeded with rye, coiffed to a uniform 2 Z\x inches and pampered by an underground sprinkler system. Although he has a lawn service, he likes to tend to the edging and the mowing himself, twice weekly this time of year.

"I have a love affair with grass," he says with a shy grin.

It's OK. It's springtime in the suburbs, and lawn guys like Ralph can hardly wait to get going. In the coming weeks, they'll seed, feed, weed, whack, trim, spray, water and clip the bejeezus out of their grass in an endless quest for perfection.

Americans spend $40 billion a year on lawn care, according to the turf-grass industry and the federal government. That's roughly equal to the gross domestic product of Vietnam.

And it's totally understandable in Ralph's case. He manages sports facilities around the country and is an encyclopedia on the subject of converting fields from baseball to soccer to rock concert and back again.

"No way can I have a crappy lawn," Ralph, 73, says.

But how to explain generations of typical Americans' lawn lust?

Ted Steinberg, an environmental historian at Case Western Reserve University in Cleveland, attributes it to the rise in consumer culture, the marketing of "the perfect lawn" by companies that make lawn-care products, and the post-World War II housing boom that opened up the nation's suburbs.

Looming large in Steinberg's analysis is Abe Levitt, who inserted a covenant in his Levittown, Pa., deeds requiring homeowners to cut the grass once a week between April and November. And he made sure they conformed.

"The perfect lawn became the national landscape," says Steinberg, who embraced the idea, too.

Like generations of young boys growing up on Long Island, Steinberg, now 45, followed his father around the yard as he mowed.

His father was a fanatic, so the Steinberg lawn was a perfect carpet. It had one type of grass, neat edges, a buzz cut, and, thanks to lawn-care products for every conceivable "problem," no weeds or pests. And it required a great deal of water and gasoline to maintain.

In his new book, "American Green: The Obsessive Quest for the Perfect Lawn (Norton, $24.95), Steinberg calls this the "industrial lawn." It's an ideal that, like the perfect body, is illusory — and dependent on a noisy, heavily polluting and potentially dangerous array of equipment.

"I am not anti-lawn. I have a lawn, and I use it," says the married father of two from Shaker Heights, Ohio. "My problem is with the perfect lawn."

But that's what people want, argues Tom Delaney, government-affairs director for the Professional Landcare Network, an industry group. "They want the uniformity of a lawn. They don't want dandelions in it and a bunch of weeds."

A thick, green lawn has aesthetic appeal, Delaney says: It increases home values and telegraphs a message of order and success. That's been true for decades, he says, and remains the ideal for most Americans.

Matt Rieke has loved mowing since he was kid in Whitefish Bay, Wis. He liked the feel of pushing the big Lawn-Boy around the yard. He liked being outside, lost in its loud hum. And he liked doing work that had instant, tangible results.

Now 38 and fortified with both M.D. and M.B.A. degrees, Rieke works as a venture capitalist in the biotech field — about as far from the old days as a guy can get. But he still loves cutting the grass.

"I don't obsess on it. That's a waste of time," he protests, prompting giggles from his wife, physician Sara Slattery, 37. "But I definitely care for it."

That's obvious. Thanks to his — and his lawn service's — efforts, his Wynnewood, Pa., lawn is neat, green, seeded, trimmed. But with three young children, Rieke says, it's well-used. And that's fine.

That may be the middle ground between obsessive and free-spirited. Even Delaney acknowledges that there are "people that might want a lot more nature to their landscape," adding water features, plantings, and different kinds of grass.

"There's not a single way to do this or to care for your property," Delaney says. "There are several approaches to get to the same result."

Steinberg, too, senses a growing interest in what he calls "the enlightenment lawn." That's an imperfect lawn with less grass, perhaps no grass, and more space devoted to animal- and environment-friendly plantings. It uses less water and gasoline and trades chemical treatments for organic.

Kristina Shore and her husband, Scott, are on board. In the year since they and their three children moved into a 1920 stone house in Ardmore, Pa., they've cut away six inches of grass and invasive ivy and hacked down "icky things" such as overgrown barberry in the front yard.

It may take a year or two, but they dream of transforming the yard into a formal rose garden, like her father had. They envision stone paths and seating and clusters of bushy hybrid teas. Among her favorites are the spicy-scented Double Delight and the salmon pink Helen Traubel, named for the Wagnerian soprano.

"We don't want any lawn in the front," says Shore, 49, a soprano herself who sings classical religious music.

"I'm sorry," she says, "I don't really like lawns. I think they're kind of unimaginative. Everyone has a lawn. A garden has so much more interest."

Shore has already replaced the grass in a 12-foot-by-5-foot patch by the front steps with flowers and herbs, including yarrow, sage, coral bells and daisies. She plans to keep the backyard grassy.

Some have forsaken grass altogether.

Four years ago, when Beverly and Tony Di Sciascio of Mount Royal, N.J., put an in-ground pool behind their new home, they decided to surround it with a product called JM Synthetic Grass Surfacing (www.jmsyntheticgrass.com). They figured upkeep would be minimal and they wouldn't have to worry about grass in the pool.

JM Synthetic says overall its residential market is growing. Made of soft plastic, the fake stuff has its own drainage system and weed barrier, and can be custom-designed to allow for living plants and flowers. Beverly says few people guess it's not real.