Vital Strife examines the close yet puzzling relationship between sleep and ethical care in early modernity. The plays, poems, and philosophical essays at the heart of this book--by Jasper Heywood, William Shakespeare, Edmund Spenser, John Milton, and Margaret Cavendish--explore the unconscious motions of corporeal life and the drowsy forms of sentience at the boundaries of human thought and intentionality. Benjamin Parris shows how these writers, although trained under the Renaissance humanist paradigm of attentive care, begin to dissolve the humanist coupling of virtue with vigilance by giving credence to the vital power of sleep. In contrast to humanist thinkers who equated sleep with carelessness, these writers draw on the ancient Stoic principle of oikeiôsis--the process of orienting the living being toward its proper objects of care, beginning with itself--in asserting the value of sleep, while underscoring insomnia's threat to the ethical flourishing of persons and polity alike. Parris offers an important revaluation of Stoic philosophy, which has too often been misconstrued as renouncing feeling and sympathetic connection with others. With its striking new account of the reception of Stoicism and attitudes toward sleep and sleeplessness in early modern thought, Vital Strife reveals the period's mounting concern with the regenerative nature of physical life and its elaboration of a newfound ethics of care.