The contributors to The Harmony of the Sphere include professional historians of science, philosophers of science, and scientists, who offer different perspectives from which Kant’s and Herschel’s systems can be approached. The title, The Harmony of the Sphere, is an evocative one. In it, the reader will hear an echo of Kepler’s cosmological system. In fact, however, this title refers to the new model of the world defended by Kant and Herschel. This model dismissed the idea of a finite static cosmos, and introduced an evolutionary perspective. This volume represents a contribution to studies that integrate the history and philosophy of science. It presents, for the first time, a comparative study of Kant and Herschel in order to highlight the historical and philosophical underpinnings of their worldviews – worldviews which would in turn have a crucial influence on the development of nineteenth- and twentieth-century astronomy and cosmology.