“Chico: "Here's the book, it's a dollar"
Groucho: "Here's a ten, and shoot the change."
Chico: "I don't have change I'd have to give you nine more books.”

Source: My Reading Life

Source: Key of Knowledge

Attributed

"Humanity", Ch.II "Ideologies: A way to live", Part IV

Letter to Maxwell Perkins (21 October 1946); p. 80
To Reach Eternity (1989)
Context: Also by the way, I have found a title for this book. From Here to Eternity. Taken from the "Whiffenpoof" song, of Yale drinking fame. It goes: "We are little black sheep who have gone astray, baa... baa... baa. Gentlemen songsters out on a spree, damned from here to eternity. God have mercy on such as we. Baa, etc." Maybe it's maudlin, but so am I. I get chills every time I sing it, even when sober.

Phlogiston interview (1995)
Context: When I started writing my first novel,... And Call Me Conrad, they always say: "Write about what you know" and I said "Well, if I get a nice sort of combination SF and Fantasy with these resonances from Greek Mythology it might be pretty good. It would also give me a chance to start filling in my background on all those things I don't know much about but should if I want to be an SF writer."
So I sat down and made a list of everything I felt I should know more about. Astrophysics, oceanography, marine biology, genetics... Then when I'd finished the list I read one book in each of these areas. When I'd finished I went back and read a second book until I'd read ten books in each area. I thought that it wouldn't turn me into a terrific, fantastic expert but I'd at least have enough material there to know if I was saying something wrong. And I'd also know where to turn to get the information I want to make it right.
While I was doing this, to keep the words and cheques flowing I wrote books involving mythology. And once I started picking up things involving astrophysics I'd write stories that played with those sorts of things. So that's why I started out with mythology.

Source: The Shadow of the Wind