A new book, Mary Poppins, She Wrote: The Life of P. L. Travers, is out detailing the life and times of P.L. Travers, best known as the author of the eight Mary Poppins books. Looks like there are interesting details about Travers relationship with the Walt Disney Company, such as this:
After long coveting the rights to "Mary Poppins," Disney finally got
what he wanted. The deal made Travers a millionaire, but she was deeply
conflicted about the movie. She harangued Disney and the writers with
pages of notes about items she felt were untrue to the spirit of her
books. At the première (which she attended, although not at Disney’s
invitation), the 65-year-old Travers wept.
The CS Monitor has more in their review of the book.