From I Love Typography:
[A] new kind of serialized fiction . . . first appeared in London in the 1830s. It wasn’t Charles Dickens or Mary Shelley but it was cheap — only a penny — easy to read, entertaining, and extraordinarily popular.
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The emergence of the penny dreadful in England coincided with improved literacy. Nationwide educational reforms launched in the 1830s aimed to eventually provide universal, free, and compulsory state-funded education. In England, when printing was introduced in the 1470s, literacy was likely under 10%. By the 1830s, literacy rates were about 66% and 50% for men and women, respectively. By 1900 the literacy rate had risen to 97%. What’s more, in the nineteenth century there was sustained and unprecedented population growth. In England, between 1800 and 1850 the population doubled; it then doubled again between 1850 and 1900! That growth was accompanied by a marked demographic shift: already by the 1820s almost half of the UK’s population was under 20! Not only did the period mark an almost exponential increase in mass-produced and cheap print, on scales inconceivable prior to the Industrial Revolution, but it found a global mass market of readers — an increasingly large number of whom were young and literate. It’s in this environment that the penny dreadful made its debut.
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Before the nineteenth century, there wasn’t much in the way of fun and entertaining reading material for children. In fact, children’s literature as a genre was a pretty late starter, only getting off the ground in the eighteenth century, and even then it was usually didactic, pious, and moralizing — not particularly fun. The first children’s periodical, The Lilliputian Magazine, published by John Newbery, didn’t appear until 1751. By the late 1790s, Churches and religious organizations had begun to publish children’s periodicals and Sunday School magazines, but again they were rather stuffy and conservative, not really the kind of thing that children were excited to read. But that was about to change.
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In summing up the nineteenth-century ‘reading revolution’, historian Dr Mary Hammond writes: ‘The period 1830–1914 saw some of the greatest changes in readerships and the types and availability of reading material ever experienced in the Western world.’* By the start of that period, serialized fiction was already becoming hugely popular. It’s how Charles Dickens got his start with the serialization of The Pickwick Papers in 1836–37. But most early serialized fiction was intended for adult readers. What’s more, although books were now cheaper than they’d ever been, they were still beyond a working child’s meagre wages; for example, The Pickwick Papers was published in twenty 32-page installments, but at 5 shillings (1 shilling = 12 pennies) per installment, it was far too expensive for most working class adults, let alone children.
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Enter the penny dreadful, typically eight or sixteen pages, printed on cheap paper, taking its serialized story cues from gothic thrillers of the previous century. Most of the stories are now forgotten, but one notable exception is everyone’s favorite homicidal barber, Sweeney Todd. Before he appeared in the pages of a book, he was butchering his victims and selling their remains as meat pies next door in a penny dreadful serial, ‘The String of Pearls: A Romance’, published in The People’s Periodical in 1846.
Link to the rest at I Love Typography
There are lots of images taken from Penney Dreadfuls at the OP.
Here’s a page from Sweeney Todd from Wikipedia: