5 books in series

Groundbook of the Metaphysics of Morals

Groundbook of the Metaphysics of Morals is a 5-book series with 5 released primary works first released in 1785 with contributions by Immanuel Kant and Mary Gregor.

Fundamental Principles of the Metaphysics of Morals
The Moral Law: Groundwork of the Metaphysics of Morals
Groundwork of the Metaphysics of Morals
Fundamentación para una metafísica de las costumbres
Grounding for the Metaphysics of Morals/On a Supposed Right to Lie Because of Philanthropic Concerns