Who invented radio (i.e., 'radio' in the most general sense, including wireless telegraphy as well as broadcasting)? A fascinating question that even today --- more than 100 years after the first transatlantic transmissions --- is not entirely resolved and fuels heated discussions. On January 17, 2003, I happend to listened to an NPR interview with Princess Mary Elettra Elena Anna Marconi, the daughter of Guglielmo Marconi. Even though most history books attribute the invention of radio to Marconi, the ingenious inventor Nikola Tesla may in fact deserve the credit. Tesla had already lectured on the subject back in 1893. Both inventors have filed patents including, among others, Tesla's basic radio patents (patent no. 645,576 and 649,621) in 1897, and Marconi's (British) patent in June of 1896. Marconi's U.S. patent applications were at first rejected for reason of prior art (Tesla's patents), but surprisingly in 1904 a new patent examiner, possibly for political reasons, also granted a radio patent to Marconi (patent no. 763,772). An endless patent dispute was finally (at least from a legal perspective) decided in 1943, only a few months after Tesla's death, when the US Supreme Court gave Tesla's patent priority over Marconi's. Legal opinions on the Supreme Court ruling are published in favor of either side by A. David Wunsch and Wallace Edward Brand in the Mercurians newsletter 'Antenna' and well worth the read. Overall, it seems that Tesla indeed invented radio. Nevertheless, Marconi deserves great credit for his vigorous commercialization of wireless telegraphy and radio.

Other Links:
PBS Show on Tesla
Who invented radio?
Tesla Museum in Belgrade
Patents by Nikola Tesla (PDF; requires Adobe Acrobat Reader)