One of her most widely known characters is Noddy, intended for beginning readers. However, her main forte is the young readers' novels, where children ride out their own adventures with minimal adult help. In this genre, particularly popular series include the Famous Five (consisting of 21 novels, 1942 - 1963, based on four children and their dog), the Five Find-Outers and Dog, (15 novels, 1943-1961, where five children regularly outwit the local police) as well as the Secret Seven (15 novels, 1949 - 1963, a society of seven children who solve various mysteries).
Her work involves children's adventure stories, and fantasy, sometimes involving magic. Her books were and still are enormously popular in Britain, Malta, India, Pakistan, New Zealand, Sri Lanka, Singapore, and Australia; and as translations in the former Yugoslavia, Japan, and across most of the globe. Her work has been translated into nearly 90 languages.