This chapter focuses on the essays of Transcendentalists such as Henry David Thoreau, Ralph Waldo Emerson, and Margaret Fuller who used writing as a spiritual and philosophical tool. This special form of prose allowed them to write themselves, and thus Transcendentalism as a movement, into being, creating a flexible, open-ended, and experimental instrument for the radical self-fashioning of an emergent sensibility: the American individual as a freestanding soul, entire in (him)self, capable of encompassing all the potential of the cosmos. The resulting works forever stamped this most antinomian of genres with the Transcendentalist’s indelible signature. The chapter traces the movement back to Harvard College in the 1820s and ’30s, where students and faculty discussed spirituality, philosophy, and the art of writing. The chapter traces the influence of this convergence and of key figures like the Unitarian preacher William Ellery Channing on the burgeoning movement. The chapter’s final pages highlight how central Transcendentalism has been to the American essay tradition, with writers today of greatly varying backgrounds absorbing its lessons and style into their own writing.