What a great book! And what a stupendous character is Gully Foyle! Brutish, nasty, self-centered, focussed, he hurts anyone and everyone in the drive for his answer: why he was left so dependent, so lonely.
And what a tremendous growth and rebirth he experiences! From ape to cosmic being, the stereotype common man, not recommended for promotion, becomes the newborn man of Clarke's 2001, a dream, a vision of tomorrow.
Pay attention to his epiphany: It isn't necessary to have something to believe in. It's only necessary to believe that somewhere there's something worthy of belief.
An outstanding, enriching addition to life.