Nikola Tesla was a tireless inventor whose technology revolutionized the electrical age of the 20th century. Regarded by many historians as an eccentric genius, Tesla gained international fame for his invention of a system of alternating current that made possible the distribution of electricity over vast distances and is the basis for the electrical grid that powers 21st century life. But the visionary Tesla imagined much more—robots, radio, radar, remote control, the wireless transmission of messages and pictures, and harnessing the wind and sun to provide free energy to all. But the image of Tesla as a “mad scientist” came to overshadow his reputation as a brilliant innovator. Even before his death in 1943, he was largely forgotten, his name obscured by Thomas Edison—his hero, one-time employer, and rival. Tesla's sense of the future has inspired renewed interest in the man, as his vision of a world connected by wireless technology has become a reality.