The Happiest Baby on the Block

In The Happiest Baby on the Block, pediatrician Harvey Karp argues that human infants are born roughly three months "premature" compared with other mammals, and that this unfinished state explains much of early crying. His central claim is that newborns still expect the conditions of the womb, so parents can trigger a calming reflex by recreating them. Karp packages this into the "5 S's": swaddling, side or stomach position, shushing, swinging, and sucking. Used together, he says, they can soothe even colicky babies and help them sleep longer. The book grew out of Karp's Los Angeles pediatric practice and his study of infant crying, including his interest in why unexplained fussiness peaks around six weeks and fades near three to four months, which he calls the "fourth trimester." He distinguishes this from traditional soothing advice by stressing vigorous, jiggly motion and loud white noise rather than gentle patting. Karp also addresses parental guilt, breastfeeding, sleep safety, and when crying may signal illness or developmental issues. The tone is reassuring and practical, with step-by-step demonstrations and troubleshooting for each S, such as how to swaddle tightly without overheating and how to hold a baby on the side or stomach only while awake and supervised. He does not promise a magic cure for every infant, but presents the 5 S's as a repeatable method for reducing crying and improving sleep during the first months.