The introduction offers an original discussion of the emergence of Gaia, informed by the extant literature while centered on the letters exchanged in their working relationship, drawing new connections and insights from these previously unpublished materials. It highlights a range of themes that animate their conversations and the history of Gaia as a scientific and philosophical idea. The introduction treats the first encounter of Lovelock and Margulis; their individual careers and professional personae; material and social aspects of their collaboration; questions of authorship; the range of scientific disciplines necessary to Gaia's elaboration; matters of geography and institutions; the significance of the occasional disagreements between Lovelock and Margulis over how best to characterize Gaia; Gaia's reception within different disciplinary and social contexts, including evolutionary biology, Earth sciences, systems sciences, exo- and astrobiology, and a range of political and environmental cultures. The introduction concludes with a chronological outline of the correspondence.

Here we provide an overview of Part I, introducing the main themes we will address as they relate to the science of careers. We ask what mechanisms drive productivity and impact, how creativity is distributed over the course of a career, and whether a scientist’s highest impact work can tell us anything about the other work they produce.