The British physicist and electrical engineer, Oliver Heaviside, 1850-1925. Having no formal education, Heaviside worked initially as a tele- graph operator until deafness forced him to stop. Applying mathematics to electric circuits and the theory of telegraphy, he formulated the concepts of impedance, conductance and self-inductance. He showed how audio signals could be transmitted down cables without distortion; showed how a telephone line can carry many conversations simultaneously (multiplexing); then suggested a reflecting layer in the upper atmosphere to radio signals (now the Heaviside layer). He wrote: Electromagnetic Theory (3 volumes) but his unified field theory was lost.