Penny dreadful is a pejorative term used to refer to cheap popular serial literature produced during the nineteenth century in the United Kingdom. The term is roughly interchangeable with penny horrible, penny awful, and penny blood. The term typically referred to a story published in weekly parts, each costing one penny.

The subject matter of these stories was typically sensational, focusing on the exploits of detectives, criminals, or supernatural entities. While the term "penny dreadful" was originally used in reference to a specific type of literature circulating in mid-Victorian Britain, it came to encompass a variety of publications that featured cheap sensational fiction, such as story papers and booklet "libraries". The penny dreadfuls were printed on cheap wood pulp paper and were aimed at young working class males.

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