Fenn wrote a series of children's books for her nephews and nieces, inspired by
Anna Laetitia Barbauld's
Lessons for Children (1778-9), and in 1782 she wrote to the children's publisher
John Marshall asking whether he would be willing to publish them. Between 1782 and 1812, he published numerous books by Fenn, often anonymously or under the pseudonyms Mrs. Teachwell or Mrs. Lovechild. The games emphasize conversation and the child's own world; they encourage the mother to answer the child's questions and to spontaneously teach when the child is interested in learning. In 1795, Fenn had a falling out with her publisher, John Marshall, and moved her business to
Elizabeth Newbery's firm and publishers in
Norwich. Throughout her career, Fenn never received any royalties for her work, only free distribution copies of her works. ==Life and death in Dereham==