Shelley and Vitality reassesses Percy Shelley's engagement with late eighteenth- and early nineteenth-century science and medicine, specifically his knowledge and use of theories on the nature of life presented in the debate between surgeons John Abernethy and William Lawrence. Ruston presents new biographical information to link Shelley to a medical circle and St Bartholomew's Hospital in London. In poems such as Prometheus Unbound, Adonis, and the Defence of Poetry, Shelley employs the vocabulary and ideas of this new science to express social, political and poetic questions and ideals. The medical search for a principal of life is shown to emerge from the political challenges of the day and to confront issues which are characteristically Shelleyan: the desired selflessness of the Romantic subject, sensibility, mutability, and the necessity of repositioning humankind in a newly conceived, active universe. The Shelley who emerges from this study is a more consistently materialist thinker than is usually acknowledged. Making use of rare books and manuscripts, Shelley and Vitality will be of interest to students and scholars of Shelley and the links between science and literature.