Who invented the 'Theremin'?

Lev Sergeyevich Termen (1896 – 1993), better known as Leon Theremin, was a Russian inventor, most famous for his invention of the theremin, one of the first electronic musical instruments and the first to be mass-produced. It was a by-product of his development of spy equipment.

Theremin created the Buran eavesdropping system. A precursor to the modern laser microphone, it worked by using a low-power infrared beam from a distance to detect sound vibrations in glass windows. The head of the secret police organization NKVD (the predecessor of the KGB), used the Buran device to spy on the British, French and US embassies in Moscow.

Theremin invented another listening device called 'The Thing', hidden in a replica of the Great Seal of the United States carved in wood. In 1945, Soviet school children presented the concealed bug to the U.S. Ambassador as a "gesture of friendship" to the USSR's World War II ally. It hung in the ambassador’s residential office in Moscow and intercepted confidential conversations there during the first seven years of the Cold War, until it was accidentally discovered in 1952.

The theremin is an electronic musical instrument controlled without physical contact by the performer (who is known as a thereminist). Two antennas sense the position of the player's hands and control audio oscillators. The sound of the instrument is often associated with eerie situations and has been used in several science fiction and horror movie soundtracks.