Silvanus P. Thompson, born in 1851, was elected to the Royal Society in 1891. He wrote numerous technical books and manuals on electricity, magnetism, dynamos, and optics, as well as several popular biographies of prominent scientists. Thompson died in 1916. Martin Gardner, born in 1914, has written several reviews for" The New York Review of Books" and was a "Scientific American "columnist for over twenty-five years. He lives in Hendersonville, North Carolina.