57 years of author interviews available for free...
...at the Paris Review website.
From the 1982 interview with P.L. Travers:
I’ve always been interested in the Mother Goddess. Not long ago, a young person, whom I don’t know very well, sent a message to a mutual friend that said: “I’m an addict of Mary Poppins, and I want you to ask P. L. Travers if Mary Poppins is not really the Mother Goddess.” So, I sent back a message: “Well, I’ve only recently come to see that. She is either the Mother Goddess or one of her creatures—that is, if we’re going to look for mythological or fairy-tale origins of Mary Poppins.”
(via Nicola Griffith)