An American writer of children's and young adult fiction, she is known for novels such as The Leftover Elf and Truth and Consequences. Her 1974 work, The Edge of Next Year, was a finalist for the National Book Award.
She attended Columbia University and Gibbs College. She drafted her first novel, To Tell Your Love, on yellow legal pads.
Her work, The Noonday Friends, received the Newbery Honor in 1966.
She was born in Massachusetts and raised in New York. In 1964, she married Thomas C. Jaleski.
She and Lisa Armstrong both contributed to Cosmopolitan magazine.