While Hegel's concept of second nature has now received substantial attention from commentators, relatively little has been said about the place of this concept in the Phenomenology of Spirit. This neglect is understandable, since Hegel does not explicitly use the phrase second nature' in this text. Nonetheless, several closely related phrases reveal the centrality of this concept to the Phenomenology's structure. In this paper, I develop new interpretations of the figures natural consciousness', natural notion', and inorganic nature', in order to elucidate the distinctive concept of second nature at work in the Phenomenology. I will argue that this concept of second nature supplements the official' version, developed in the Encyclopedia, with an unofficial' version that prefigures its use in critical theory. At the same time, this reconstruction will allow us to see how the Phenomenology essentially documents spirit's acquisition of a second nature'.