This study participates in the ongoing scholarly effort to re-appraise the penny dreadful phenomenon as a cornerstone of literary history and of popular culture, both within the nineteenth century and the development of Victorian popular fiction and beyond its specific context. The growing presence of these cheap entertaining Victorian texts in contemporary popular culture - through television series, musicals and literature - signals that it is high time to bestow more systematic and comprehensive attention to these publications. To do so, Penny Dreadfuls: The Circulation Patterns of a Victorian Popular Genre conceptualises the notion of circulation as a tool for analysis. This book considers different aspects of circulation. The weaponisation of the penny dreadfuls' successful circulation by its critics highlights tensions in the literary marketplace over the hegemonic discourse of what should and should not be read, which mirror the broader issue of contemporary changes on a social, cultural and political level. In addition, the penny dreadfuls' consumption patterns and behaviour within the literary marketplace and within society are also marked by their circulation between different historically popular genres: within the network of late-eighteenth-century and early-nineteenth-century literature and culture, they refuse to remain within clear boundaries and constantly reinvent themselves at the intersection of several trends that constituted the popular, such as oral storytelling, sensationalism and the Gothic. Beyond the nineteenth century, their patterns of circulation develop diachronically, too, in the open-ended circulation of the penny dreadfuls across time through neo-Victorianism and the gradual transformation of the penny dreadfuls into a cultural reference. Through the lens of the concept of circulation which pervades the penny dreadfuls' history and content, this book reassesses the impact of the penny dreadfuls on nineteenth-century print culture and entertainment, as well as on contemporary popular culture. This book demonstrates the importance of these publications to better understand broader notions of popular culture and to keep deconstructing such binaries as 'high' and 'low' culture. Further than sales numbers, circulation interweaves numerous aspects of popular culture and of this publishing phenomenon. An analysis of these patterns helps decode many aspects of the penny dreadfuls' life and afterlife, as it reveals how their material aspect is intimately interwoven with their seriality, their cultural significance, the reactions they provoked and their actual content. The resulting picture informs us about the nineteenth century's social history and culture, about class warfare and political change, and about the evolution of literature over the past two hundred and fifty years.