This is the first collected edition of the letters of Humphry Davy. Davy is a significant figure in both the history of science and literary history. One of the foremost chemists of the early nineteenth century, he was the first person to inhale nitrous oxide. He pioneered electrochemistry, using the Voltaic pile to isolate more chemical elements than any other scientist; and he invented the miners' safety lamp that came to be known as the 'Davy lamp'. His lectures and papers played a key part in the professionalization of science, in the growth of scientific institutions, and in the emergence of scientific disciplines. He was the protégé of Thomas Beddoes and Joseph Banks, and the mentor of Michael Faraday. He was also a poet, and a friend of poets, including Wordsworth, Southey, Scott, and Byron. The edition contains fully annotated transcriptions of correspondence (much previously unpublished) with such figures as Joseph Banks, Thomas Beddoes, Jöns Jacob Berzelius, Samuel Taylor Coleridge, Michael Faraday, Joseph Louis Gay-Lussac, the Herschels, the Marcets, Marc-Auguste Pictet, Nicolas-Théodore de Saussure, James Watt, Josiah Wedgwood, William Hyde Wollaston, and Thomas Young. The edition throws new light on Davy, on the histories of science and literature, and on the social history of the early nineteenth century. It illuminates scientific controversies over the safety lamp, the Board of Longitude, the Geological Society, and the Royal Society. It offers new perspectives on the 1790s poetry of Wordsworth, Coleridge, and Southey. It illuminates women's literary networks, reveals the links between science and government, and casts light on provincial and dissenting intellectual networks, among Quakers and Unitarians.