"Économie libidinale" is Lyotard's early major work and at the same time his most problematic writing. Published in 1974, the book remained largely overlooked in Germany despite an initial German edition (1984), even though it represents a milestone not only in Lyotard's philosophy: a "book of crisis" that marks his departure from long-held positions within the group "Socialisme ou barbarie" and his break with Marxism. This rupture is reflected in an unusual, even completely misplaced tone for the academic field: Lyotard himself characterized it as "malicious," as "livre méchant." His sharp critique of the Marxists culminates in a theory of passions that almost self-destructively avoids the theoretical in terms of conceptual fixation, leading to an unheard-of, even scandalous defense of libidinous exchange.