Michael Kelly Finnigan was an American keyboard player and vocalist, his speciality being the B3 Hammond organ. Working primarily as a freelance studio musician and touring player, he played with a wide variety of musicians in pop, rock, blues and jazz.

The Hammond organ is an electric organ invented by Laurens Hammond and John M. Hanert and first manufactured in 1935. Multiple models have been produced, most of which use sliding drawbars to vary sounds. Until 1975, Hammond organs generated sound by creating an electric current from rotating a metal tonewheel near an electromagnetic pickup, and then strengthening the signal with an amplifier to drive a speaker cabinet. The organ is commonly used with the Leslie speaker.