As Cluster opens, the alien envoy Pnotl of Sphere Knyfh seeks help from Sphere Sol in a shared galactic-level crisis: Galaxy Andromeda has discovered the secret of energy transfer and intends to use it to steal the basic energy of the Milky Way Galaxy.

Knyfh offers the secret of aura transfer on the understanding that Sphere Sol will spread the technology to help create a galactic coalition to find and defeat agents of Andromeda.

Sixteen-year-old Dug has yet to be impressed by a computer game, but that's before he gets hooked by Companions of Xanth-and the beguilingly beautiful princess-serpent he's chosen to guide him. Nada Naga has her work cut out for her keeping Dug's eyes on the magical prize . . . and off of her human form.

Mute is science fantasy of mutation and psi: special mental powers. The protagonist, Knot, is a double mutant: He has a physical deformity, and the psi power to make others forget him. He's satisfied with his life - until the lovely Finesse walks into his life to recruit him for a dangerous galactic mission. She is aided by two small animal mutants: a telepathic weasel and a clairvoyant crab.

Though he was later accused of every crime and sexual perversion in the galaxy, Hope Hubris began as an innocent. Because he defended his older sister against the violent lusts of a wealthy scion, Hope and his peasant family were forced to flee Callisto, one of the moons of Jupiter. Pursued by the bloodthirsty scions across the airless desert, they barely escaped with their lives. The illegal space bubble was overcrowded with refugees, all hoping to reach Jupiter for asylum.

Humanoid robots are surely in our future, but their uses are likely to be limited to body guarding, childcare, companionship, and sex. Other chores can better be done by smart non-humanoid machines designed for those specific tasks. But for these limited purposes, the best robots must be so realistic that they are indistinguishable from live people. Elasa is such a robot. You can't tell her nature if she doesn't reveal it. You can talk with her, embrace her, kiss her, and she is the perfect woman. Until she becomes the first conscious robot.

Somewhere on the frontier between thought and reality exists the Discworld, a parallel time and place that might sound and smell very much like our own, but which looks completely different. Particularly as it’s carried though space on the back of a giant turtle (sex unknown). It plays by different rules. But then, some things are the same everywhere. The Disc’s very existence is about to be threatened by a strange new blight: the world’s first tourist, upon whose survival rests the peace and prosperity of the land.

Nickie Haflinger had lived several lifetimes...but technically never existed. He was originally a fugitive from Tarnover, the incredibly powerful government think tank that educated him. First he had broken his identity code - then he made his escape. Now he needed to find a way to restore sanity and freedom to the computerized masses and save a world nearing the brink of disaster. He didn’t care how he accomplished this - but the government did. That’s when his Tarnover teachers took him back into their labs, where Nickie Haflinger was set up to receive a whole new education.

Welcome to Ringworld, an intermediate step between Dyson Spheres and planets. The gravitational force created by a rotation on its axis of 770 miles per second means no need for a roof. Walls 1,000 miles high at each rim will let in the sun and prevent much air from escaping. Larry Niven's novel, Ringworld, is the winner of the 1970 Hugo Award for Best Novel, the 1970 Nebula Award for Best Novel, and the 1972 Ditmars, an Australian award for Best International Science Fiction.

In this, the first novel of the best-selling Incarnations of Immortality series, Piers Anthony combines a deeply moving examination of the meaning of life and death with a gripping story of romance and loyalty, all set in a world of magic and technical wizardry.

Imajica is an epic beyond compare: vast in conception, obsessively detailed in execution, and apocalyptic in its resolution. At its heart lies the sensualist and master art forger Gentle, whose life unravels when he encounters Judith Odell, whose power to influence the destinies of men is vaster than she knows, and Pie "oh" pah, an alien assassin who comes from a hidden dimension.