Laxmi Bachanalaya
Legally available public-domain books and openly licensed reading materials.
Vatsyayana
Mary Wollstonecraft
John Stuart Mill
Havelock Ellis
Anonymous
Stendhal
John Harvey Kellogg
B. G. Jefferis and J. L. Nichols
comte de Honoré-Gabriel de Riqueti Mirabeau
Otto Weininger
H. L. Mencken
Iwan Bloch
Hans Fehlinger
Thomas W. Shannon
Sarah Grimké
August Bebel
D. Ph. van Vloten Elderinck
Mary Astell
Various
Catharine Esther Beecher
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.