This essay introduces the Romantic-period political reformer and polymath John Thelwall and takes stock of his rapid critical renaissance over the past decade. The announcement of a new archival find, a copy of a seventeenth-century play owned and annotated by Thelwall, serves to highlight the range of his interests and activities. Presenting Thelwall as a leading representative of “romantic sociability,” I situate him within wider social and intellectual networks than have hitherto been mapped, and I raise questions about the coherence and continuity of his diverse pursuits—literary, political, and scientific—that demand further attention. My brief overview of the essays collected here emphasizes how they address those questions, engaging with one another, with existing Thelwall scholarship, and with Romantic studies more generally. This introduction also sets forth the rationale for the volume as part of the larger project John Thelwall: Recovery and Reassessments (forthcoming) and explains why Romantic Circles is an especially appropriate venue for that project’s efforts to advance Thelwall studies by reconnecting text, voice, and image in the dynamic way for which Thelwall himself was renowned.