In 2005, author Anne Brashares created a cult-like following with the publication of Sisterhood of the Traveling Pants. The life-long friendship shared by four girls—Carmen, Bridget, Lena and Tibby—now spans four novels, and the four core characters have shared many life experiences, chronicled and laid bare for readers to observe.

On the night before the girls plan to go their separate ways for the summer, Carmen buys a pair of secondhand jeans for $3.49. The jeans ostensibly are nothing special; they have a few bleach stains and are even pretty worn in spots. The four friends agree that the pants will go to whomever they fit best, but the girls soon learn that the jeans are "magical pants" that fit each of the girls perfectly, despite their differences in build. Because the friends are slated to spend the summer apart from one another, the girls devise a plan to stay in touch: the pants will be mailed from girl to girl. That night, the group of friends takes the vow of the Sisterhood of the Traveling Pants. Over the course of the summer following their sophomore year of high school, each girl finds herself in a difficult situation in which the pants play a key role.

Lena heads to Greece to visit her grandparents, and while there, she finds love with a local boy. Bridget goes to soccer camp in Baja, Mexico, where she finds herself in a difficult situation with the coach. Carmen travels to South Carolina, where she will stay with her father. Upon her arrival, she discovers that her father is remarried and has a new family. And Tibby begrudgingly plans to remain at home in Maryland working a boring, minimum wage job. Little does she know that she will develop a meaningful friendship with a twelve-year-old who has terminal leukemia.

Sisterhood of the Traveling Pants and its first sequel, The Second Summer of the Sisterhood, have been made into major motion pictures starring America Ferrera, Alexis Bledel, Amber Tamblyn, and Blake Lively.