"Halmos, Paul R.
... the student skit at Christmas contained a plaintive line: 'Give us Master's exams that our faculty can pass, or give us a faculty that can pass our Master's exams.'
I Want to be a Mathematician, Washington: MAA Spectrum, 1985."

"Hadamard, Jacques
The shortest path between two truths in the real domain passes through the complex domain.
Quoted in The Mathematical Intelligencer, v. 13, no. 1, Winter 1991."

"Graham, Ronald
It wouild be very discouraging if somewhere down the line you could ask a computer if the Riemann hypothesis is correct and it said, `Yes, it is true, but you won't be able to understand the proof.'
John Horgan. Scientific American 269:4 (October 1993) 92-103."

"Gordon, P
This is not mathematics, it is theology.
[On being exposed to Hilbert's work in invariant theory.]
Quoted in P. Davis and R. Hersh The Mathematical Experience, Boston: Birkh�ser, 1981."

"Goedel, Kurt
I don't believe in natural science.
[Said to physicist John Bahcall.]
Ed Regis, Who Got Einstein's Office? Addison Wesley, 1987."

"Gauss, Karl Friedrich (1777-1855)
You know that I write slowly. This is chiefly because I am never satisfied until I have said as much as possible in a few words, and writing briefly takes far more time than writing at length.
In G. Simmons Calculus Gems, New York: McGraw Hill inc., 1992."

"Galton, [Sir] Francis (1822-1911)
Whenever you can, count.
In J. R. Newman (ed.) The World of Mathematics, New York: Simon and Schuster, 1956."