Complex sentence: Bowman is led through a metamorphosis from a material being to an entity of pure energy, an entity referred to in the novel "2001" as the "Star Child".
Split into simpler sentences: Bowman is led through a metamorphosis from a material being to an entity of pure energy. This entity, and David Bowman's incarnation of himself in this state, is referred to in the "2001" book as the "Star Child".