Duke was born in New York City on August 1, 1956. She had said that reading was a favorite pastime all through childhood, and in an interview for Something About the Author noted that Louise Fitzhugh’s Harriet the Spy was a fictional character she modeled, right down to keeping tabs on the people in her neighborhood. “I think I owe Harriet my first conscious awareness of the act of writing as important and meaningful work,” she said.
She attended Duke University in the mid 1970s and also took art classes in New York City, which helped solidify her growing ambition to create picture books. Her first book, The Guinea Pig ABC (Dutton) was published in 1983 and received warm accolades for its humor and inventiveness. She followed up her debut with Guinea Pigs Far and Near (Dutton, 1984) and several other titles starring the popular critters. Duke went on to craft more than 20 picture books, writing and illustrating her own work, as well as providing illustrations for other authors including Joanna Cole and William Hooks. Duke married cartoonist Sidney Harris in 1985.