David Stipp’s short book, A Most Elegant Equation, aims to persuade the “math-averse” that “great mathematics is as provocative, beautiful, and deep as great art or literature.” His exemplar is Euler’s identity, which can be written as the gnomic formula e^iπ + 1 = 0. Stipp offers to explain what it means, why it’s true, and why it is significant as science and as art. The discussion, he says, will take pains to assume no mathematical prerequisites beyond checkbook arithmetic, and he isn’t kidding. For example, every algebraic manipulation that crops up is accompanied by a verbal paraphrase (often lengthy). A 101-word footnote on page 15 is devoted to explaining why “x = −1” means the same thing as “x + 1 = 0.”

“Euler” is Leonhard Euler, the master mathematician of the 18th century and one of the greatest of all time—also the most prolific. Publication of his collected works, begun in 1911 and ongoing, will total more than 80 large volumes. He is by all accounts an appealing character—a pious family man who, according to one contemporary, could work happily with “a child on his knees, a cat on his back.” Euler was generous in his dealings with other scholars, a good teacher, and something of a polymath who, in addition to his native German, knew Latin, Russian, French, and English and published works on mathematics, science, philosophy, and music. He could recite the entire Aeneid from memory. Euler began to lose his sight at an early age but blindness seemed if anything to increase his productivity: He worked things out in his head and dictated the results.