"Mary Poppins Opens the Door" is the third book in PL Travers' surreal series about the tough, magical nanny and London's Banks family. Travers' books are, as is often the case, are much richer things than the Disney movie. Shamefully, the movie is such a powerful icon Travers' books seem almost unknown.
She was born in Australia in 1899 and lived until 1996. She was a poet, author, student of mystic Gurdjieff and comparative myths and religion. She knew Yeats and Eliot. All these things clearly influence the stories she told about Mary Poppins and are missing from the Julie Andrews' movie.
All the books so far (I've read 3 of 5) follow the same basic pattern. Mary appears mysteriously, corrals the Banks children into order and brings them on strange trips and adventures which she later makes no indication of having any knowledge of. Then she leaves as strangely as she arrived. The following book then opens with the Banks' household having fallen into disarray after Mary's disappearance which is promptly set aright by her return.
Mary is tough, opinionated (and always right), strong willed and smart. Everywhere she goes she is treated with great deference and respect. She most assuredly does not break into song and Bert does not speak in Dick Van Dyke's atrocious Cockney accent.
Check them out. All except the last one (Mary Poppins in Cherry Tree Lane and Mary Poppins and the House Next Door) are readily available.