Humanist and scientific analyses of the Anthropocene concept may be distinctive as a coinvestigation across disciplinary borders. While scientists only in 2023 hypothesized the Anthropocene's inception in the 1950s (as measured by atomic residue), humanists have for several decades been investigating the concept as a probable reality and argue for its longer chronology. The six books reviewed here identify the early modern period, especially the eighteenth century, as a convincing moment of transition, indicating a longer era of relevant anthropogenic activity. This periodization has important implications for addressing the ongoing environmental crisis, which will require both humanist and scientific knowledge.