In collaboration with Margulis, Lovelock began work on a professional talk as the basis for a new Gaia essay. Its publication was assured when Tellus collected “Atmospheric homeostasis by and for the biosphere: the Gaia hypothesis” (Lovelock and Margulis 1974a). Margulis took on the overhaul of their first paper, which she referred to in Letter 43 as “Gaia I”: “I will rewrite Gaia I into the style appropriate for the Proc Natl Acad of Sci. For example, the title will be ‘Homeostatic Tendencies of the Earth’s Atmosphere’” (the title of Lovelock and Margulis 1974b). By February, both drafts were reaching completion: “The end would appear to be in sight at least so far as the preparation of these drafts goes. I think that they are great,” Lovelock wrote, acknowledging Margulis’s lead efforts: “Lynn you have done the writing and the organization of the papers” (Letter 47). These two essays became three as Margulis developed a separate article, “Biological modulation in the Earth’s atmosphere” (Margulis and Lovelock 1974), repurposing draft materials and diagrams while putting the biology of Gaia front and center.