Open Library
Sci-Fi
The future, written before it arrives.

First Lensman
Edward E. Smith

Edison's conquest of Mars
Garrett Putman Serviss

Captain Underpants and the Attack of the Talking Toilets
Dav Pilkey

Dragonquest
Anne McCaffrey

The Purple Cloud
M. P. Shiel

The Big Time
Fritz Leiber

Columbus of Space
Garrett Putman Serviss

The Regulators
Stephen King

The war in the air
H. G. Wells

The Foundation Trilogy
Isaac Asimov

Down and out in the Magic Kingdom
Cory Doctorow

The Book Of Three
Lloyd Alexander

Equal Rites
Terry Pratchett

Small Gods
Terry Pratchett

Captain Underpants and the Invasion of the Incredibly Naughty Cafeteria Ladies from Outer Space
Dav Pilkey

Mostly Harmless
Douglas Adams

One Shot
Lee Child

The Naked Sun
Isaac Asimov

Children of Dune
Frank Herbert

State of Fear
Michael Crichton