Much of the appeal of the series stems from its extensive use of references and allusions from a wide array of 'thinkers', including Teilhard de Chardin, John Muir, Norbert Wiener and John Keats, a Romantic poet of the 19th century, with the title of the first novel, "Hyperion" taken from Keats' poem "Hyperion". Similarly, the title of Simmons' third novel is from Keats' poem "Endymion". Quotes from actual Keats poems and the fictional 'Cantos of Martin Silenus' are also interspersed throughout the novels.
'Hyperion' is the name of a planet where much of the action in the series takes place, described as having one-fifth less gravity than Earth, with peculiar indigenous flora and fauna, notably electricity-spewing 'Tesla Trees', also noted as a "labyrinthine" planet, home to ancient subterranean labyrinths of unknown purpose.
Most importantly, Hyperion is the location of the 'Time Tombs', artifacts surrounded by 'anti-entropic' fields that allow movement through time, in a region that is also home to the 'Shrike', a menacing creature that impales its victims..