Lois Duncan stands as a formidable figure in young adult literature, her works resonating deeply with teenagers and earning the respect of educators and librarians alike. Her narratives often delve into themes of personal integrity, providing fertile ground for classroom discussions. Notably, her novel I Know What You Did Last Summer diverges from the conventional happy endings typical of young adult mysteries, offering instead a realistic portrayal laced with tragedy. Here, not all protagonists find redemption, highlighting Duncan's unique approach to storytelling.

Further cementing her prowess in the suspense and mystery genre, Duncan's subsequent works continue to explore the intricate dynamics of responsibility and group loyalty. In Killing Mr. Griffin (1978), she crafts another compelling blend of morality and mystery. The plot revolves around a group of teenagers whose impulsive decision to kidnap their strict English teacher spirals into an unintended fatality. This narrative examines the destructive power of selfishness among two group members, leading all involved into a web of guilt and deceit. Duncan adeptly portrays how easily Susan, one of the characters, is influenced by Mark’s reckless plans, culminating in the teacher's tragic death during a heart attack.

In recognition of her contributions to young adult literature, Duncan was honored in 1992 as the fourth recipient of the prestigious Margaret Edwards Award. Presented by the American Library Association, this accolade acknowledges authors whose works provide young adults with insightful perspectives on their personal and social roles. The award highlighted several of Duncan’s novels, including I Know What You Did Last Summer and Killing Mr. Griffin, for their exploration of a diverse array of individuals—spanning the fortunate and underprivileged, the strong and weak, the virtuous and wicked, as well as the impatient and submissive.

Duncan's literary achievements have garnered her widespread acclaim from readers, critics, and fellow authors. Many of her novels have received accolades from distinguished organizations such as the Mystery Writers of America, The New York Times, and the American Library Association. Central to these celebrated works are characters who grapple with truth and courage, ultimately embarking on journeys toward maturity. Through her gripping narratives, Duncan not only entertains but also challenges her young readers to reflect on the complexities of human nature and the moral choices that define us.