The Night's Dawn Trilogy

Author Peter F. Hamilton's Night's Dawn trilogy consists of three epic science fiction novels: The Reality Dysfunction, The Neutronium Alchemist, and The Naked God. A collection of short stories, A Second Chance at Eden, shares the same universe, and The Confederation Handbook documents that universe in non-fiction style.

Warning: Wikipedia contains spoilers.

The sprawling narrative deals with a far future where humanity struggles and wages war against past souls flooding back into the land of the living via possession (Al Capone is among the returnees). And that's just the beginning. Hamilton's future is expansive and primarily optimistic, with huge sentient space-cities that can closely resemble a natural Eden. He extrapolates on current trends concerning the blurring of technology with biology, and environmental devastation. But Hamilton pulls no punches on humanity's darker side. Poverty, sexual exploitation and cruelty still dog our civilizations in Night's Dawn.