(April 13, 1911 – September 2, 2004)

Inventor of the Leslie loudspeaker. Finding the sound of the Hammond Tonewheel Organ impressive but lacking resonance in a small space, he set about devising a speaker that would enhance the sound. The result was the Leslie speaker.

Born in Danville, Illinois, Leslie worked in radio repair and at the Naval Research Laboratory in Washington, D.C., during World War II.

He failed to persuade Laurens Hammond to licence his speaker system and build it into the organ and the external add-on he manufactured and marketed was obstructed by Hammond until his death, after which the Hammond business did in 1978 acquire the right to instal a Leslie speaker in the organ cabinet.