Nikola Tesla (1856-1943) and one of his coils, circa 1899 (double exposure).
His greatest inventions were the AC motor, conceived in 1882, and the polyphase system to generate and distribute AC power (which is used the world over today). Some of Tesla's other inventions include the steam turbine, VTOL aircraft and radio (Tesla first demonstrated radio in 1893, two years before Marconi's first demonstration, Tesla's patents were upheld by the U.S. Supreme court, over Marconi's, in 1963).