Laxmi Bachanalaya
Legally available public-domain books and openly licensed reading materials.
Alfred Martin
R. T. Claridge
Sebastian Kneipp
Charles Munde
Joel Shew
John Harvey Kellogg
John Smith
J. H. Holdsworth
Various
Diogenes [pseudonym]
Aloysius Binder
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.