Lois Duncan grew up in Sarasota, Florida and from early childhood she knew she wanted to be a writer. She submitted her first story to a magazine at the age of 10 and made her first sale at 13. Throughout her high-school years, she wrote regularly for young people's publications, particularly Seventeen Magazine.

Duncan is best known for her brilliant psychological suspense novels. She was drawn to this genre because those were the books he enjoyed reading. Of her writing technique, she once said, "Although I've been told that some authors start writing with only a general idea in mind and let their stories evolve on their own, I couldn't work that way. My books are tightly plotted and carefully constructed; every sentence is there for a reason. Personally, I can't imagine writing a book without knowing exactly how it's going to end. It would be like setting out on a cross-country trip without a road map."