'I should have written you after my first reading of The Living Currency; it was already breath-taking and I should have responded. After reading it a few more times, I know it is the best book of our times.' Letter to Pierre Klossowski from Michel Foucault, winter 1970. Living Currency is the first English translation of Klossowski's La monnaie vivante. It offers an analysis of economic production as a mechanism of psychic production of desires and is a key work from this often overlooked but wonderfully creative French thinker. The two essays presented here are Klossowski's last theoretical works; they are essential to our understanding of this original and important thinker.