In It's Not What You Expect, fourteen-year-old twins, Oliver and Carla, must cope with their father's absence when he leaves the family to go to New York City to write a book. Angel Face is a tragic story of a boy who must learn to live without his mother. The protagonist, Jason, is not doing well in his school life or love life because his family is falling apart. Other books with male protagonists are Going Backwards and No More Saturday Nights.

Both stories portray young men with life-changing problems. Love Is One of the Choices and Older Men have female main characters who make adult decisions while they are still teen-agers.

There have been three adaptations of Klein's work: "Mom, the Wolf Man and Me" (record or cassette; Caedmon, 1977), Mom, the Wolfman and Me (film; Time-Life Productions, 1979), and "Confessions of an Only Child...