American engineer and inventor Laurens Hammond filed U.S. Patent 1,956,350^[1] for a new type of "electrical musical instrument" that could recreate a pipe organ–type sound. The invention was unveiled to the public in April 1935 and the first model, the Model A, was made available in June of that year. The organ was first used for popular music by Milt Herth, who played it live on WIND (AM) soon after it was invented.^{[2] [3]} The Hammond organ was widely used in United States military chapels and post theatres during the Second World War, and returning soldiers' familiarity with the instrument may have helped contribute to its popularity in the post-war period.^[4]

Hammond had intended his invention to be an affordable substitute for pipe organs, as a replacement for the piano in middle-class homes, and as an instrument for radio broadcasting. However, by the 1950s, jazz musicians such as Jimmy Smith began to use the organ's distinctive sound. By the 1960s, the Hammond became popular with pop groups and was used on the British pirate station Radio 390. In Britain the organ became associated with elevator music and ice rinks music. However, the overdriven sound of the Hammond gained a new image when it became part of 1960s and 1970s rock with artists like Steve Winwood, Keith Emerson, and Rick Wakeman.

Hammond tonewheel organs are preferred among many vintage organ enthusiasts, the most popular models also having tube amplifiers. Some of the later Hammond models combine tonewheel generation with solid-state amplifiers, with the latest models of that era being fully solid state. Hammond is now owned by Suzuki Company. Hammond-Suzuki makes digital organs that replicate the tonewheel organ sound (see "Clones" below).

References:
All information was pulled from http://en.wikipedia.org/wiki/Hammond_organ.