Laxmi Bachanalaya
Legally available public-domain books and openly licensed reading materials.
Havelock Ellis
Thomas William Lawson
L. Oppenheim
Hugo Grotius
Evan James MacGillivray
Various
David Hilbert
Coalition for Networked Information
Florence Kreisler Greenbaum
H. G. Wells
John Fiske
James Boyle
Thomas Erskine Holland
Baron John Francis Arundell Arundell of Wardour
George Grafton Wilson and George Fox Tucker
These books are free to read. Each is in the public domain in the United States; check your own country's rules before you copy or share one.