First published in 1653, The Compleat Angler is one of the most influential environmental texts ever written. Addressing a politically and religiously polarized nation devastated by warfare, disease, ecological degradation, and climate change, Izaak Walton’s famous fishing treatise stages a radical thought experiment: how might humanity’s enhanced relationship with the natural world generate a new kind of sustaining—and sustainable—social order beyond the traditional boundaries of the church, the state, and the biological family? Challenging the current scholarly consensus that reads Walton’s how-to manual as a conservative polemic camouflaged by fishlore, Marjorie Swann examines this richly complicated portrayal of the natural world through an ecocritical lens and explores other neglected aspects of Walton’s writings, including his depictions of social hierarchy, gender, and sexuality. In the process, Swann analyzes a host of noncanonical environmental texts and provides a groundbreaking reappraisal of Charles Cotton’s “Part II” of The Compleat Angler. This study extends the hydrological turn in early modern ecocriticism and demonstrates how, as a genre, angling manuals provide new insights into the environmental, cultural, social, and literary history of early modern England. Taking its place alongside landmark works of ecocriticism such as Green Shakespeare and Milton and Ecology, this fresh and timely reassessment of The Compleat Angler rightly ranks Izaak Walton among the most important environmental writers of the early modern era.