The Hammond organ is an electric organ invented by Laurens Hammond in 1935. It uses a unique system of tonewheels to produce sound, which gives it a distinctive, rich tone. The instrument became popular in various music genres, including jazz, rock, and gospel. Hammond organs are known for their drawbars, which allow players to manipulate the sound by adjusting the volume of different harmonics. They often feature a built-in Leslie speaker, which adds a swirling effect to the sound. The Hammond B-3 model is particularly famous and widely used by many musicians.