Hidden Harmonies

Is “a squared plus b squared equals c squared” more famous than “e equals mc squared?” The theorem formulated by Pythagoras has certainly been around longer than Einstein’s, thereby accruing a commensurately greater amount of lore and usage. With mathematical insight and welcome wit, Ellen and Robert Kaplan trace the influence of the Pythagorean theorem through the millennia—enlisting the help of Leonardo Da Vinci, President James Garlfield, and the Freemasons along the way.