Who is Gully Foyle, Geoffrey Fourmyle, The Burning Man, Nomad from The Stars My Destination and what is their importance?

Gully Foyle is the last remaining survivor of the Nomad. The Nomad, a merchant spaceship, was attacked in the war with the Outer Planets and left drifting in space. Foyle is a living zombie, a man who has not bothered to explore more than the minimum potential of his abilities. Driven by a desire for revenge, Foyle spends time in prison before remaking himself into Geoffrey Fourmyle. He is known as Nomad to the Scientific People and, by the end of the tale, the Burning Man.