6 books in series

Groundbook of the Metaphysics of Morals

Groundbook of the Metaphysics of Morals is a 6-book series with 6 primary works first released in 1785 with contributions by Immanuel Kant, Mary Gregor, and H.J. Paton.

Fundamental Principles of the Metaphysics of Morals
Groundwork of the Metaphysics of Morals
The Moral Law: Groundwork of the Metaphysics of Morals
Fundamentación para una metafísica de las costumbres