“Vampires. They wrote the book on possessive.”

The Paris Review interview (1982)
Context: I never wrote my books especially for children. … When I sat down to write Mary Poppins or any of the other books, I did not know children would read them. I’m sure there must be a field of “children’s literature” — I hear about it so often — but sometimes I wonder if it isn’t a label created by publishers and booksellers who also have the impossible presumption to put on books such notes as “from five to seven” or “from nine to twelve.” How can they know when a book will appeal to such and such an age?
If you look at other so-called children’s authors, you’ll see they never wrote directly for children. Though Lewis Carroll dedicated his book to Alice, I feel it was an afterthought once the whole was already committed to paper. Beatrix Potter declared, “I write to please myself!” And I think the same can be said of Milne or Tolkien or Laura Ingalls Wilder.
I certainly had no specific child in mind when I wrote Mary Poppins. How could I? If I were writing for the Japanese child who reads it in a land without staircases, how could I have written of a nanny who slides up the banister? If I were writing for the African child who reads the book in Swahili, how could I have written of umbrellas for a child who has never seen or used one?
But I suppose if there is something in my books that appeals to children, it is the result of my not having to go back to my childhood; I can, as it were, turn aside and consult it (James Joyce once wrote, “My childhood bends beside me”). If we’re completely honest, not sentimental or nostalgic, we have no idea where childhood ends and maturity begins. It is one unending thread, not a life chopped up into sections out of touch with one another.
Once, when Maurice Sendak was being interviewed on television a little after the success of Where the Wild Things Are, he was asked the usual questions: Do you have children? Do you like children? After a pause, he said with simple dignity: “I was a child.” That says it all.<!--
But don’t let me leave you with the impression that I am ungrateful to children. They have stolen much of the world’s treasure and magic in the literature they have appropriated for themselves. Think, for example, of the myths or Grimm’s fairy tales — none of which were written especially for them — this ancestral literature handed down by the folk. And so despite publishers’ labels and my own protestations about not writing especially for them, I am grateful that children have included my books in their treasure trove.

Source: Is Everyone Hanging Out Without Me?

Source: The Egoist http://www.gutenberg.org/dirs/etext99/egost11.txt (1879), Ch. 14.

"Modo di filosofare".

On his novel I Am Legend, and the inspiration for it.
The New York Times interview (1994)

Stripped (2009)

Source: Cryptic Cravings

Comment on meeting Harriet Beecher Stowe, author of Uncle Tom's Cabin, according to Charles Edward Stowe, Lyman Beecher Stowe, "How Mrs. Stowe wrote 'Uncle Tom's Cabin'", McClure's magazine 36:621 http://books.google.com/books?id=biAAAAAAYAAJ&pg=PA621&dq=%22little+woman+who+wrote+the+book+that+made+this+great+war%22 (April 1911), with a footnote stating: "Mr. Charles Edward Stowe, one of the authors of this article, accompanied his mother on this visit to Lincoln, and remembers the occasion distinctly."
Annie Fields, "Days with Mrs. Stowe", Atlantic Monthly 7:148 http://books.google.com/books?id=8F0CAAAAIAAJ&pg=PA148&dq=%22Is+this+the+little+woman+who+made+the+great+war%22 (August 1896)
Posthumous attributions
Variant: Her daughter was told that when the President heard her name he seized her hand, saying, "Is this the little woman who made the great war?"
Variant: So you are the little woman who caused this great war!