Lois Duncan began writing as a child, selling her first short story at age thirteen. From her first novel, Debutante Hill, she has gone on to write many different kinds of books, over thirty in all for young readers. Most noted for her predominant characters and plot, Duncan's style is simple and intriguing. Her plots involve normal teenagers in normal surroundings suddenly caught up in something totally unexpected, from the weird to the terrifying. Her subject matter covers anything and everything happening in the modern teenager's life, including drugs, sex, divorce, crime, identity crises, and peer pressure. Some of her characters are convincingly evil, depicted in chilling clarity by narration with a wealth of detail. The danger her teen-agers face develops quite believably, giving her stories a shade of reality making them simultaneously frightening and appealing. Even in the instances when Duncan uses the supernatural, her presentations seem realistic, the type of experiences anyone might have.

She is said to draw upon her family and acquaintances for characters, and she writes books she would enjoy reading herself. Admitting to having caused her younger brother nightmares by telling him spooky stories, Duncan has been a fan of the supernatural for years. She was a loner as a child and describes herself as an overweight, shy, daydreaming bookworm who enjoyed exploring wooded areas and isolated Florida beaches. Many of her characters and settings are based on those experiences.

Her works have won multiple awards, including The National Press Women's Award, New Mexico Press Women's Zia Award, Theta Sigma Phi Head Liner Award, Dorothy Canfield Fisher Award, and the California Young Reader's Award. Stranger with My Face was named Best Book of the Year for Young Adults by the New York Times, Library of Congress, and by the University of Iowa.

Although her plots may seem somewhat shocking, most young readers enjoy the fine style and imagination that has boosted Lois Duncan to amazing popularity.