Nikola Tesla was a Serbian-American inventor, electrical engineer, mechanical engineer, and futurist best known for his contributions to the design of the modern alternating current (AC) electricity supply system. Born in Smiljan, then part of the Austrian Empire (modern-day Croatia), Tesla demonstrated an extraordinary intellect and creativity from an early age. He studied engineering and physics in the 1870s without receiving a degree, gaining practical experience in the early 1880s working in telephony and at Continental Edison in the new electric power industry. In 1884, he emigrated to the United States, where he became a naturalized citizen. He worked for a short time at the Edison Machine Works in New York City before he struck out on his own.

Tesla's most significant contributions include the development of AC electrical systems, the Tesla coil, wireless communication, and numerous other inventions that laid the groundwork for modern electrical engineering. His rivalry with Thomas Edison, known as the 'War of Currents,' is legendary, with Tesla's AC system ultimately prevailing over Edison's direct current (DC) system for widespread electricity distribution. Despite his brilliance, Tesla struggled financially in his later years and died in relative obscurity in New York City. However, his legacy has grown posthumously, and he is now celebrated as one of history's greatest inventors and visionaries.

Tesla was known for his eccentric personality and vivid imagination. He claimed to have conceived many of his inventions in his mind before building them, a process he called 'thinking in pictures.' He also had a photographic memory and spoke eight languages. Tesla's ideas extended beyond electricity; he envisioned wireless energy transmission, global communication networks, and even thought about harnessing energy from the environment. Some of his more speculative ideas, such as a 'death ray' and wireless power transmission, have fueled myths and conspiracy theories, but his documented achievements remain foundational to modern technology.