Those for whom the term “Anthropocene” tends to evoke academic faddishness may be surprised to realize that the discourse about it is now two decades old. The term was first proposed in a 2000 paper by the atmospheric chemist Paul Crutzen and biologist Eugene Stoermer to describe the geological epoch in which human activity has come to shape the Earth itself. Since then, the concept has generated a vast amount of scholarly conversation and a wide range of interpretations, often concerning the start date of this new era: Did the “age of man” begin with the use of fire? The development of settled agriculture? The rise of capitalism? European settlement of the Americas? And so on. Although these debates have raged across the humanities and sciences for years, political theorists have largely kept their distance. As the climate crisis worsens, however, many may now be looking to play catch-up. If so, each of the three books under review here holds out the promise of helping us understand the theoretical implications of this epochal transformation.