Einstein, Albert (1879-1955) The truth of a theory is in your mind, not in your eyes. [In H. Eves, Mathematical Circles Squared, Boston: Prindle, Weber and Schmidt, 1972] Euler, Leonhard (1707-1783) Mathematicians have tried in vain to this day to discover some order in the sequence of prime numbers, and we have reason to believe that it is a mystery into which the human mind will never penetrate. [In G. Simmons,...