Laxmi Bachanalaya
Legally available public-domain books and openly licensed reading materials.
Theodor Reye
Karl Weierstrass
Hermann Sieveking
Henri Poincaré
Leo Koenigsberger
Karl Joseph Bobek
R. Clausius
Friedrich Schottky
Wolfgang Vogt
Otto Bohler
Wallie Abraham Hurwitz
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.