Dan Simmons, Hyperion (Hyperion Cantos)

A true sci-fi classic. Epic in scope; visionary in its evolution ideas, natural in its human frailties and superb in future technologies. All this blends with an exciting vision of the future of humanity in a galaxy where we have no home and a very real and powerful enemy. A time travelling machine god and shadow clouded threats, the main characters strive for the truth to the biggest questions of their time and space. All based around a prescient poem written by John Keats. Incredible and essential.