From Johann Heinrich Füssli’s 1781 oil painting The Nightmare, which was to become the iconic image of a newly emergent sensibility, to the first psychoanalytic studies culminating in “On the Nightmare” by Ernest Jones, first published in 1911, the long nineteenth century was characterised by a pervasive fascination with nightmares, both as frightening dreams and, in their personified form, evil spirits or monstrous creatures. This volume investigates the extensive and multifaceted presence of nightmares in the literature and culture of this period from a cross-disciplinary and cross-national perspective, shedding new light on the remarkably widespread nature of the nineteenth-century interest in nightmares as well as on common threads and features that inform and animate it. Its contributions by scholars from different fields reveal how nineteenth-century representations of nightmare, across and beyond Europe, explored fundamental questions about the limits of consciousness and reason, the complex interplay of body and mind, the elusive boundaries between self and other, and the dread of alterity, giving voice to deep-rooted fears and anxieties in a period when these notions were undergoing radical rethinking.