The introductory chapter elaborates definitions of two opposed but entangled poetic tendencies, calling one mortalist and the other spiritualist. It draws extended examples from John Milton (particularly from Paradise Lost [1667] and De Doctrina Christiana); from Edward Young (especially from Night Thoughts [1742–6], identified as the poem central to the study); and from several late twentieth- and early twenty-first-century Anglophone poets, including Lucie Brock-Broido, Michael Symmons Roberts, Danez Smith, Tracy K. Smith, and Kevin Young. Some of these writers, the chapter argues, surprisingly keep alive a poetics of disembodiment derived from the Enlightenment. The introduction ends with a discussion of some relevant questions in literary criticism (concerning materialism, Pre-Romanticism, historical poetics, and lyric studies) and then a personal word about the author’s perspective on the spiritualities explored in the book.