Isidore of Seville (d. 636 CE) is a crucial figure in the preservation and propagation of Classical and Patristic learning. He put such learning to varied use in his own day, in the process ensuring that it could be made useful for future generations. Because of the depth of what he preserved and the breadth of its diffusion, Pope John Paul II proclaimed Isidore the patron saint of the internet in 1997. Yet his influence was felt throughout the Middle Ages, most acutely in early medieval Western Europe. Isidore's compilations of the works of earlier authorities provided theological, pastoral, scientific and historical resources that formed an essential part of monastic curricula for centuries. Representing a cross-section of the different approaches that have been taken to Isidore's writings, these collected essays explore the sources on which Isidore drew, how he selected and arranged them for future use, and the different ways in which his legacy was appropriated by future generations across the early medieval West.