Science Fiction

Isaac Asimov

Prelude to Foundation

Foundation

Foundation and Empire

Second Foundation

Foundation's Edge

Foundation and Earth

Forward the Foundation

Asimov's Foundation series is the benchmark against which all other science fiction is measured. 

I, Robot

Isaac Asimov

100 Complete Shorts

The Gods Themselves

Nemesis

The movie was fun.  The book is much better. 100 of Asimov's best short stories. Only a few know the terrifying truth--an outcast Earth scientist, a rebellious alien inhabitant of a dying planet, a lunar-born human intuitionist who senses the imminent annihilation of the Sun. When Eugenia Insigna of the Settlement Rotor, an independent space station, discovers an unknown red dwarf star two light years from Earth, she names it Nemesis.
Robert Heinlein

Stranger in a 

Strange Land

The Moon is a 

Harsh Mistress

Job - 

A Comedy of Justice

Friday

This is the epic saga of an earthling, Valentine Michael Smith, born and educated on Mars, who arrives on our planet with many psi powers, including the ability to take control of the minds of others—and complete innocence regarding the mores of man. The Moon is a Harsh Mistress is one of the high points of modern science fiction, a novel bursting with politics, humanity, passion, innovative technical speculation, and a firm belief in the pursuit of human freedom. My favorite Heinlein work.  Funny, irreverent, thought-provoking and vivid, Job provokes you to think about religion in a way you probably never have before. Friday is the classic Heinlein heroine.  Uninhibited, tough, able and - most of all - sexy.  Friday tells the tale of an artificial woman who finds her way through a web of intrigue to start a new life as a free woman.
James Blish

Cities in Flight

Cities in Flight is an omnibus volume of four novels, originally published between 1955 and 1962, two of which are fix-ups of pieces that first appeared in various magazines in the early '50s. Despite having been conceived more than 50 years ago, and produced in episodic fashion, they stand head and shoulders above most SF available today. - Amazon.com

A Case of Conscience

The citizens of the planet Lithia are some of the most ethical sentient beings Father Ramon Ruiz-Sanchez has ever encountered. True, they have no literature, no fine arts, and don't understand the concept of recreation, but neither do they understand the concepts of greed, envy, lust, or any of the sins and vices that plague humankind. Their world seems darned near perfect. And that is just what disturbs the good Father. - Amazon.com
Anderson Gentry

The Crider Chronicles

From the publisher:

The nations of humanity thought they were alone in the Galaxy. They were wrong, and now humanity faces a threat greater than all the wars in all their history.

Don't miss this political-military thriller, set hundreds of years in the future.