Laxmi Bachanalaya
Legally available public-domain books and openly licensed reading materials.
John Caius
Charles C. Adams
Henry Mayhew
William Beebe
Gordon Stables
Mary D. Barber
United States. National Park Service
William Taplin
John Savory
Alexander von Humboldt
Various
Oliver C. Farrington
Samuel Grant Oliphant
Alfred Edmund Brehm
Ticul Alvarez
Frances E. Slaughter
Frank Hall Knowlton
Ralph Waldo Emerson
Max Geitel
Bento Serrano
Rollin H. Baker
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.