Today, nanoscience and emerging technologies weave ever more tightly into the social fabric. Scientific and technological innovations at the infinitesimal depths of matter now entail cultural, political, and philosophical ramifications of extraordi- nary scope, extending from the molecular scale to the global scale, from the physical entanglements of subatomic particles to the fiscal entanglements of transnational markets. The need to engage these technical developments and their social aspects with fine-grained precision becomes increasingly evident. This volume addresses the question of engagement by working from the bottom up: grappling with the particular, discrete operations of nanoscience and related fields in order to assess how these operations shape, and are shaped by, practices of participatory culture and civil society. It opens outward from minimal and local interactions with the molecular sciences—attending to the necessity of quantum engagements—and expands across the dimensions of history, public discourse, ecology, and political economy. Refracting the social complexities of our high-tech world, the es-says in this collection participate in the project of articulating new modes of technoscientific governance. Bringing together contributions and perspectives from experts in the social sciences, the humanities, and the natural sciences, Quantum Engagements showcases ongoing research activities of the vibrant, multidisciplinary community of S.NET, the Society for the Study of Nanoscience and Emerging Technologies.