In 1696 Isaac Newton left Cambridge University to become Warden of the Mint. When he came home one afternoon, he learned of a problem set by Johann Bernoulli as a challenge to the "great mathematicians of the world." Since Newton and Gottfried Wilhelm Leibnitz were engaged in a bitter priority dispute over the invention of calculus, it was really a challenge issued by continental mathematicians to Newton. The so-called brachistochrone problem was to determine the shape of the wire connecting two nails randomly driven into a wall which would permit a bead that is acted upon only by gravity to slide from the top nail to the bottom one in the least amount of time. Newton developed the calculus of variations and solved the problem that very night. Though he published his solution anonymously, upon examining it Bernoulli famously remarked, "I recognize the lion by his claw...