The neglect of the environment stands in sharp contrast to the embrace of other “turns” by historians in the last fifty years. The social history turn of the 1960s still remains at the center of the discipline, although reconfigured by the linguistic and cultural turns. The gender turn also dramatically reshaped the core of the discipline, as has the post-colonial. More recently, the imperial and global turns have had a profound and widespread impact. Environmental history has not had a similar impact because, in contrast to other recent turns, the environmental has not produced a powerful theoretical statement on the centrality of its perspective for making sense of history as a whole. In this lecture, economist-historian Prasannan Parthasarathi provides a way out of this impasse. Parthasarathi presents a framework for putting the natural world at the center of the writing of history, arguing that without nature historians cannot understand time. And where is history, without time?