The Minimoog was built by the legendary Bob Moog. There were four models. Model A and B were prototypes of the synth, Model C was given to musicians for testing and the last Model D was the one that finally went on sale. 

The Minimoog was the first compact synthesizer. Before that, there were only big and heavy modular walls. The handy Minimoog made it possible for bands and artists to use synthesizers as stage equipment for the first time.