Magnificat (Galactic Milieu Trilogy #3) by Julian May

Dealing mainly with the Metapsychic Rebellion of 2083, Magnificat focuses mainly on Marc, a powerful metapsychic and member of the mighty Remillard family. He believes that the only logical way to speed the evolution of the Galactic mind is through artifical enhancement of the human brain. Thus he plans to remove and artifically nurture the brains of newborn test-tube babies, subjecting them to intense metapsychic training.

But not all the Remillard family agree with Marc's megalomania. His brother Jack the Bodiless - a mind born into a body that eventually destroyed itself - has had to endure a similar fate as a matter of survival, evolving into a powerful, poignant figure utterly alone in his uniqueness. He is opposed to Marc's plans and his sentiments are shared by some of the other members of the Remillard family. And so, Jack must decide how best to hinder his brother's scheme without compromising human metapsychics in the larger community of the Milieu.

As the final volume in the epic Galactic Milieu trilogy (Jack the Bodiless, Diamond Mask), Magnificat is a powerful and compelling conclusion to Julian May's highly successful series detailing the human struggle in a new galactic civilisation.