To discuss The Hyperion Cantos is to discuss a work that transcends genre. While it wears the skin of space opera—complete with faster-than-light travel, galactic politics, and terrifying alien threats—its bones are constructed from the marrow of John Keats’ poetry, the philosophy of time, and the structural brilliance of Chaucer. This is an exploration of a universe that is dying, not with a bang, but with the slow, suffocating squeeze of inevitability, watched over by a god who may be insane.
Most readers agree that Hyperion and The Fall of Hyperion form one seamless novel (the first ending on a literal cliffhanger). These two books are Simmons at his densest, most experimental, and most rewarding. Dan Simmons - The Hyperion Cantos