“Reading a book is like re-writing it for yourself. You bring to a novel, anything you read, all your experience of the world. You bring your history and you read it in your own terms.”

The Paris Review interview (1982)
Context: 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.”
I’ve spent years thinking about it because the questions I’ve been asked, very perceptive questions by readers, have led me to examine what I wrote. The book was entirely spontaneous and not invented, not thought out. I never said, “Well, I’ll write a story about Mother Goddess and call it Mary Poppins.” It didn’t happen like that. I cannot summon up inspiration; I myself am summoned.
Once, when I was in the United States, I went to see a psychologist. It was during the war when I was feeling very cut off. I thought, Well, these people in psychology always want to see the kinds of things you’ve done, so I took as many of my books as were then written. I went and met the man, and he gave me another appointment. And at the next appointment the books were handed back to me with the words: “You know, you don’t really need me. All you need to do is read your own books.”
That was so interesting to me. I began to see, thinking about it, that people who write spontaneously as I do, not with invention, never really read their own books to learn from them. And I set myself to reading them. Every now and then I found myself saying, “But this is true. How did she know?” And then I realized that she is me. Now I can say much more about Mary Poppins because what was known to me in my blood and instincts has now come up to the surface in my head.

Source: A Northern Light

"Why Read New Books?" The New York Review of Books (11 November 2014).

"Friendly Advice [Written impromptu by the author on delivering this book, already prepared for publication, to the printer" (1949)
All and Everything: Beelzebub's Tales to His Grandson (1950)