Immanuel Kant
Kant developed his moral philosophy in three works: "Groundwork of the Metaphysic of Morals" (1785), "Critique of Practical Reason" (1788), and "Metaphysics of Morals" (1797).
Joseph Green (merchant)
Around 1764 Green met Kant and became a close member of his circle of friends. Kant went often to Green's house outside of Königsberg in Juditten. Green shared with Kant a deep appreciation of the ideas of David Hume and Jean-Jaques Rousseau, in addition, Green could provide as perspective of the outside world that was helpful for Kant. Meeting on a regular basis, Kant discussed his work with him, so every sentence of his "Critique of Pure Reason" prior to the 1781 publication. Kant also entrusted Green with his money.