A Solitary Blue is a novel by Cynthia Voigt published in 1983. The book follows Jeff Greene, a second-grader whose mother leaves the family. After visiting her one year at her family home, he begins to write her letters and send her things. However, Jeff's love is not reciprocated and during a subsequent visit she is more interested in her new boyfriend. He becomes aloof and depressed, though eventually his detached father begins to help him. The novel deals with themes of love, family and loneliness.