 In the introduction to the "Time's Eye", Clarke describes the premise as "neither a prequel nor a sequel" to "Space Odyssey", but an "orthoquel" (a neologism coined by Clarke for this purpose, combining the word "sequel" with "ortho-", the Greek prefix meaning "straight" or "perpendicular", and alluding to the fact that time is orthogonal to space in relativity theory).In "Space Odyssey", a race of benevolent godlike aliens with highly advanced technology decides to use machines called "monoliths" to travel across the galaxy with the intention to ensure the survival chances of intelligent life (including Earth) and "test" and "weed out" species that have no possibility for intelligence.In the "Time Odyssey" series, not-so-benevolent godlike aliens start an endless mission to regulate the development of sentient life throughout the known universe, in order to prevent all other species from harnessing too much of its energy, which would only accelerate the inevitable heat death of the universe.