“Funny, drama-fueled, and full of Jackson's breezy wit… Brilliant.” —Coco Mellors, New York Times bestselling author of Blue Sisters

An ambitious young woman insinuates herself into a tight-knit social set, shaking up friendships and marriages in a small seaside town. A frothy novel of love, money, sex, and friendship, from the New York Times bestselling author of Pineapple Street (“Laugh-out-loud-good.” —Harper’s Bazaar)

When Caroline Lash arrives in Greenhead, Massachusetts, she falls head-over-heels for Van Whittaker, a fleece-wearing, litter-collecting, kayak enthusiast with long, floppy hair and the personality of a Border collie. Born and raised in this picturesque coastal village, Van runs with the same crowd he did as a kid: His ex-girlfriend, Bailey, a beautiful girl who attracts men like moths to a flame; Augusta, old money, horsey, and snobbish; and Fran, surrounded by brothers and sons, too fed up with boys to ever consider marrying one.

Together, the group runs wild through the marshes, beaches, and bars of Greenhead, drinking on houseboats, spending long afternoons sunbathing with their children, and playing games the way they always have. But when Bailey discovers that she is pregnant with Van’s baby, the delicate balance of the group’s friendship is thrown off. Soon Caroline is cast out of the circle and what she does next—in a potent mix of fury and heartbreak—exposes long-held secrets and works the entire town of Greenhead into a lather. Dazzlingly funny, sexy, and as juicy as it is astute, The Shampoo Effect is a story of late-night parties, early mornings with small children, the dawn of midlife, and a group of old friends finally growing up despite all their best efforts to the contrary.