But Thursday, he was in Durham, helping the Ellises settle baby Owen, not yet 6 weeks old. More than 150 people watched as Karp showed the Durham couple how just the right swaddle, just the right hold and just the right shush could calm the boy in seconds.

"OK, sweet boy," he cooed.

It worked.

"We've got to work on our swaddling technique," dad Matt Ellis said afterward.

Karp spoke Thursday at a community seminar, kicking off the 20th anniversary celebration of Welcome Baby.

Welcome Baby offers support, programs, a lending library and car seat information for parents and caregivers with young children, from newborn to age 5, in Durham.

Karp has 30 years of experience as a pediatrician and is an assistant professor of pediatrics at the UCLA School of Medicine.

But his real rise to household name came with the publication of "The Happiest Baby on the Block" in 2002.

Karp says babies are born before they're really ready for the world. Parents, he says, need to think of the first three months as the fourth trimester. Constantly holding and rocking a baby isn't going to spoil them, he says, after constant rocking and holding in their mother's womb.

Karp says his techniques, which involve swaddling, holding on the side or stomach, shushing, rocking and sucking, will calm crying babies quickly and help them sleep one to three hours more at night.

With promises like that, bleary-eyed parents of newborns have made his book, a national bestseller.

Karp followed up in 2004 with "The Happiest Toddler on the Block," co-written with Chapel Hill author Paula Spencer. Again, he promises to end, or at least drastically reduce, what most people think come with toddlerhood -- tantrums.

Now the books are coupled with DVDs, so parents can see exactly how to swaddle their newborn or talk to their toddler. And more than 2,300 certified instructors are spreading the Karp method across the country.

Karlye Butler, mother to a 2 1/2-year-old boy and an almost 5-month-old girl, hopes to be one. The Chapel Hill mom has followed Karp's methods with both of her children. She gives his DVDs to all her friends.

"I saw the DVD when pregnant with my first child and immediately starting using Dr. Karp's methods and every single one worked," Butler said.

William Meyers, an associate clinical professor at Duke University who has led a postpartum depression support group for more than 18 years, said he first heard about Karp from mothers in his group. Now, he offers the DVDs to some women who tell him they're not able to soothe their babies.

Meyers helped bring Karp to Durham this week.

"We are breathlessly waiting for 'The Happiest Teenager on the Block,'" Meyers joked as he introduced Karp.