Maddy is sixteen. Smart, funny, and profound, she has loyal friends, a mother with whom she's unusually close, a father she's never met, devoted grandparents, and a crush on a boy named Jack. Maddy also has cancer. Living in the shadow of uncertainty, she is forced to grow up fast.

All the Water in the World is the story of a family doing its best when faced with the worst. Told in the alternating voices of Maddy and her mother, Eve, the narrative moves between the family's lake house in Pennsylvania; their home in Washington, DC; and London, where Maddy's father, Antonio, lives. Hungry for experience, Maddy seeks out her first romantic relationship, finds solace in music and art, and tracks down Antonio. She continually tests the depths and limits of her closeness with her mother, while Eve has to come to terms with the daughter she only partly knows, in a world she can't control.

With unforgettable voices that range from tender to funny, despairing to defiant, this novel illuminates the transformative power of love, humor, and hope.