I wrote this list several years ago and ran out of steam towards the end, but it's a good summary of my favorites.
1. Shockwave Rider, John Brunner
Distopian vision of a time not too far from now when the rate of change has gotten too high for most people to cope. The main character is an ultra-talented hacker searching for wisdom. He finds it in a small Utopian Californian town from whence he launches a digital revolution using computer viruses. Written before the advent of PC’s.
2. Stand On Zanabar, John Brunner
Distopian vision of a time not too far from now when population pressure has gotten too high for most people to cope. The novel weaves together many styles. It has two main plot lines and a raft of secondary characters which flesh out this remarkable vision.
3. Speaker for the Dead, Orson Scott Card
A truly remarkable novel about prejudice, redemption and cultural misunderstanding. The main character, Andrew (Ender) Wiggins from Enders Game is a socio-religious sleuth trying to explain the deaths of several people in the small human settlement on a planet containing the only other sentient race we have found but haven’t exterminated. Chock full of unexpected revelations that lead to healing.
4. Ender’s Game, Orson Scott Card
Andrew (Ender) Wiggins is a young boy with a talent for military strategy who is being trained to stop the threat of alien invaders. Will he be trained in time to make a difference? A gripping read.
5. Dune, Frank Herbert
The one source for the drug that allows faster than light space travel is the planet Dune. Political intrigue about the control of Dune in an interstellar empire revolves around the son of a star-lord. The novel explodes into a struggle for religious and ecological salvation.
6. The Chronicles of Narnia, C. S. Lewis
Fantasy for young adults about a magical place called Narnia that you can to get from here. Right and wrong are obvious, and the children who find their way to Narnia become better people from the experience.
7. The Lord of the Rings, J. R. R. Tolkien
There is a great evil in Middle Earth threatening to conquer all. If the evil Sauron can recover His One Ring, then all will be lost. If the forces of Good can destroy the Ring, all will be saved. Dwarves, Elves, Hobbits, Troll, Wizards and Orcs all inhabit a tale full of deception, betrayal, valor, rebirth, desperation and struggles against long odds.
8. The Foundation Trilogy, Isaac Asimov
An interstellar dark age is coming, and one man (Harry Seldon) has the mathematics to prove it. Will his efforts and those of his successors be able to minimize the darkness?
9. The Stars My Destination, Alfred Bester
People have figured out how to teleport themselves around, but their range is limited. Can anyone figure out how to jump further to interplanetary distances? The answer rests in the mind of a deranged man suffering from synesthesia.
10. Norstrillia, Cordwainer Smith
Drugs providing the indefinite prolongation of human life are produced only on one planet from giant diseased sheep. With the help of an heirloom battle-computer one boy corners the market on the immortality elixir and buys Earth and everything on it. He goes there and receives the psychological healing he seeks from the wisdom of a cat-man and the love of a beautiful cat-woman.
11. The Lensman Series, E. E. “Doc” Smith
Good Guys vs. Bad Guys in a militaristic showdown which spans two galaxies. The Bad Guys have a ruthless, compassionless hierarchy. The Good Guys have a ruthless, compassionate hierarchy. An arms race between the two advances with each book in the series. Oh, yeah, and the Bad Guys sell drugs.
12. Stranger In A Strange Land, Robert Heinlein
The only survivor of a expedition to Mars is a boy who was conceived on the way there and is subsequently raised by Martians. He returns to Earth and discovers what it means to be human and establishes a polyamorous, love-without-limits cult.
13. Jesus On Mars, Philip Jose Farmer
Reviewing a photographic mapping of Mars, scientists discover a human-sized door on the surface with the letters Alpha and Omega inscribed on it. An expedition is sent and discovers under the surface a human settlement of Jews lead by a being claiming to be Jesus. The conservative Christian leader of the expedition has to grapple with the difference between his version of Christianity and that being practiced by the settlement.
14. Time Enough For Love, Robert Heinlein
Lazarus Long was born at the turn of the 20th Century and has lived a couple thousand years. He has become bored and depressed. In searching for something he hasn’t done, several stories of his long life are told. Ultimately, to cheer him up, scientists figure out how to send him back in time where he lives out an oedipal fantasy with his mom.
15. The Centrifugal Rickshaw Dancer, William John Wadkins
The Lagrange Corporation owns Earth as well as the habitations orbiting the Earth. A revolution is fomenting in the Grand Sphere, the largest of the habitations in space. This cyberpunk predecessor is full of inventive language and plot twists.
16. Going to See the End of the Sky, William John Wadkins
Urdon Wee is dead and leading the revolution against the Corporation. He achieved enlightenment by being kissed by a beautiful woman, being punched in the face by a strong man and drinking a powerful drug within seconds of each other. Now, his vision of the future of humanity conflicts with that of the man who punched him, and their struggle is played out through the control and influence of the lives of three children from Catchcage.
17. Bridge of Birds, Barry Hughart
The children of the village have all simultaneously fallen into a mysterious coma. Number Ten Ox seeks the help of Lee Kao (who has a slight flaw in his character). The master and the young villager sleuth their way through a series of adventures which not only saves the lives of the children but also corrects a wrong which has troubled the Heavenly Emperor for centuries.
18. Out On Blue Six, Ian MacDonald
Computer programs have evolved to be smarter than people, and so people’s lives are benignly controlled by software gods. A very few are dissatisfied with being defined and controlled, and a young yuppie-caste cartoonist follows her dreams of something more into a rag-tag group of guerrilla-theater actors and into the arms of an incarnated software god. Oh, yeah, and there is an intensely loyal army of genetically enhanced raccoons.
19. The Saraband of Lost Time, Richard Grant
Richard Grant’s first novel. A haunting and strange story of a war that nobody really understands.
20. Tex and Molly in the Afterlife, Richard Grant
Tex and Molly die at the end of the first chapter, and their adventures begin. Can they save a forest in Maine from the introduction of a genetically ruthless species of conifer designed by the evil forestry mega-corp? Will their ecological protest group survive their disappearance? What do the mites have to do with all of this?
21. Startade Rising, David Brin
It seems like every chapter in this novel introduces an idea that would normally be the basis for a sci-fi novel of its own. Let’s see. The nearest five galaxies, including our own, are thoroughly populated by an ancient intergalactic culture. Planets are generally allowed to go fallow once a species has ended its life-span and new species are uplifted to sentience by the old. The prestige of a species is measured by how many species it has uplifted. Earth was somehow forgotten, and Humanity is an unheard-of “wolfling” species. We have the audacity to question the way things are done and foment an intergalactic power struggle by discovering artifacts that are possibly those of the First Ancestors. The ship which made the tempestuous discovery is mostly crewed by dolphins uplifted by men. The novel plots their efforts to elude the armadas which are chasing them and reach a political accord in which humanity won’t be destroyed.
22. The Mists of Avalon, Miriam Zimmer Bradley
A retelling of the legend of Arthur from the perspective of Morgana. Thoroughly feminist and pagan.
23. The Hitchhiker’s Guide to the Galaxy, Douglas Adams
The novelization of the outstanding comedy-sci fi radio series. The Earth gets destroyed in the first chapter. Arthur Dent is mostly the only human survivor. He and a strange group of beings seek the reasons why. The mice, after all, were very upset about it.
24. The Restaurant of the End of the Universe, Douglas Adams
Arthur Dent’s adventures continue. Arthur and his friends (?) are blown-up and find themselves at the end of time where there is a really posh restaurant (“It’s not so much an afterlife as an apres vie.”) Oh, yeah, and Marvin, the paranoid android, repeatedly sticks his head in a bucket of water.
25. A Mask for General, Lisa Goldstein
Post-apocalyptic Berkeley is the setting for a novel about how Art conquers all.
26. Dangerous Visions, Harlan Elison, Ed.
Still the greatest sci-fi short-story collection of all time. It includes Farmer’s “Riders of the Purple Wage”, a fantastic novella about what it means to be an artist; Leiber’s “Going To Roll The Bones”, a surreal fantasy about dicing with the devil, the choices we make and taking the long way home; and Sturgeon’s “If All Men Were Brothers, Would You Let One Marry Your Sister”, a novella about the relativism of morality.
27. Rite of Passage, Alexei Panshin
The children of a huge interstellar ship are admitted into adulthood only after undergoing a survival trial on a planet. A lovely novel about the process of becoming an adult.
28. Door Into Fire, Diane Duane
A sword and sorcery adventure in a land with no homophobia, and where the Goddess is known and loved by all (literally by a few lucky adventurers). Centers on a man who has the gift of magic which is rare for men there. In addition, to an on-again, off-again relationship with a handsome prince, he falls in love with a fire elemental.
29. So You Want to Be a Wizard?, Diane Duane
A young girl learns to defend herself from bullies after she discovers a magical book in the public library which teaches her how to be wizard. But every wizard must confront The Adversary, an embodiment of the entropic forces of the Universe.
30. A Wrinkle in Time, Madeline L’Engle
A magical novel about the joy of individuality. A group of normal Earth children confront an oppressive, conformist culture on a distant planet.
31. The Dark is Rising, Susan Cooper
The seventh son of a seventh son is introduced to magic in an extremely Celtic adventure in a modern setting.
32. Childhood’s End, Arthur C. Clark
Mankind’s saviors are aliens that look like the classic depiction of the Devil. They stop the warfare and bring advancements, but what are their true intentions?
33. To Your Scattered Bodies Go, Philip Jose Farmer
The main character is killed in the first paragraph. He awakens on an earth transformed into one long, meandering river along with everyone else who has ever lived. How the heck did that happen and why?
34. The Darkover books, Miriam Zimmer Bradley
Darkover is a planet that was settled in an early colonization effort. Isolated from the rest of human interstellar culture for a long time, it has developed a unique culture of its own, a patriarchal feudal culture lead by psychics. The books explore themes of feminism in an extremely patriarchal culture and the impact of technology on indigenous cultures.
35. The Once and Future King,, E. B. White
The full Arthurian cycle in the form of a twentieth century novel.
36. Dahlgren, Samuel R. Delany
A strange novel about what it means to be an artist. Set in a mildly futuristic city somehow cut-off from the rest of the world in its own private apocalypse.
37. On Wings of Song, Thomsa Disch
With the help of electronic stimulation, some people can liberate their conscious from their bodies. However, the vast majority of the United States has become oppressively conservative and so “flying” is taboo except in the decaying liberality of the cities. The story of a small town boy who never learns to fly but sparks a cultural revolution by singing about it.
38. The Thomas Covenant Trilogy, Stephan Donaldson
Thomas is an author in a small American town who has contracted Hanson’s disease: Leprosy. He hits his head and finds himself in a fantasy world where he is instantly healed. He can not afford to believe in the reality of the world he finds himself because he would lose the diligence necessary to survive with the disease. And yet everyone looks to him to be a hero. An innovative fantasy trilogy with an ending that avoids being clichéd.
39. On a Pale Horse, Piers Anthony
A suicidally depressed man in a world of technology and magic attempts to shoot himself, but instead accidentally kills Death who was coming for him. The man becomes Death, but decides to be a compassionate one in the face of temptations from the Devil.
40. Pilgrimage and No Different Flesh, Zenna Henderson
The People crash landed on the Earth at the turn of the century. Most live in an isolated, insular settlement on Mount Baldly but a few got scattered in the crash. The People seem to be human, but have psychic powers like flight and telekinesis. Cited in the English translation of the Nag Hamadi Library as a modern literary work exhibiting gnostic themes.
41. The Bast Mysteries, Rosemary Edghill
Bast is the magical name of a neo-pagan New Yorker who repeatedly finds herself in the middle of another mysterious murder. The best exploration of the modern witchcraft movement and its culture to date.
42. Lord Valentine’s Castle, Robert Silverberg
43. Shadow of the Torturer, Gene Wolf
44. The Illuminatus Trilogy, Robert Shea and Robert Anton Wilson
The ultimate paranoid conspiracy and Erisian fantasy novels of all time. The governments of the world are controlled by layer after layer of secret organizations and nefarious cabals. At the center of the web are the Illuminati. Strongly influenced by the Principia Discordia, and brilliant in its own right.
45. Lord of Light, Robert Zelazny
46. The Earthsea series, Ursula K. Leguin