This paper examines the relation between the verse stanzas and the prose notes (both the extensive footnotes and the even more extensive 'additional notes') of Erasmus or The Origin of Society: A Poem. With Philosophic Notes (1803) in an effort to engage with the complex interweaving of science and literature that forms Darwin's work and increasingly informs Romantic Studies. Beginning with the simple assertion that the notes are far more integral to the text than the subordination implied in the titular 'with' might suggest - in fact, that the notes are, in some important ways, the point of the text - I argue that what critics often refer to as Darwin's 'masterwork' interrogates the very notion of 'mastery' itself by working at once to perform and to foster a critical sense of what we might call 'interdisciplinarity': an effort neither to erect nor to erode disciplinary boundaries at points of intersection but an interest in engaging with the 'space' of the boundary itself. As Darwin notes in the preface, 'The Poem, which is here offered to the Public, does not pretend to instruct by deep researches of reasoning; its aim is simply to amuse by bringing distinctly to the imagination the beautiful and sublime images of the operations of Nature in the order, as the Author believes, in which the progressive course of time presented them.' On the one hand, this claim clearly conveys Darwin's concern with instruction, with 'bringing distinctly to the imagination' and the 'deep researches of reasoning,' even as it downplays; perhaps, more 'traditional' modes of teaching and even, by extension, works to revise our understanding of what is worth teaching. On the other hand, it suggests that a Romantic concern with the beautiful and sublime is as at home in the 'deep researches of reasoning' and the 'operations of Nature' as it is in any poem. And, however, we may choose to inflect that claim; the text is more than simply a didactic poem teaching a proto-evolutionary, clearly medicalized version of biological, sociological and cultural development. It is an extensive commentary on the interrelation of the medical and the social, the biological and the poetic and, not least, on the nature of didacticism itself, on the hows and whys of instructing and learning in an environment and at a time when the limits of the known and the knowable and the sense of promise and anxiety fostered by changing disciplinary boundaries were under constant scrutiny. By examining the interaction between the 'main' text and the paratext, I explore how one of the period's most diverse thinkers and writers negotiated the diversity of knowledge and modes of knowing that made his work so popular and influential and, most importantly, how he taught and can still teach ways for readers to manage the critical if contentious interdisciplinarity that will continue to dominate our own deep researches. [ABSTRACT FROM AUTHOR]