Though there is now a vast body of work detailing Dickens's extensive interests in contemporary science, technology, and medicine, still there is an overriding sense that Dickens was in energetic contact with scientific knowledge but had no precise role in its constitution, creation, or contestation. In this essay, I argue instead that Dickens was one of the most powerful communicators of scientific knowledge in the mid-Victorian period. Drawing on James A. Secord's model of “knowledge in transit,” the idea that the content of scientific knowledge is arrived at at the same time as audiences for knowledge are constituted or imagined, I also argue that Dickens had a significant role to play in shaping the practices, objects, and values of scientific work. If we have lost sight of this Dickens, I argue, it is because the kinds of science he advocated and the power he wielded threatened other literary-scientific practitioners—including G. H. Lewes—who reshaped Dickens's reception in ways that suited their own aims and agendas. Dickens—a vocal exponent of mesmerists, spontaneous combustionists, sanitary campaigners, early-development hypothesizers, and fantastical engineers—had a far more direct and central role in scientific culture than has yet been understood.