Erotic literature comprises fictional and factual stories and accounts of eros – passionate, romantic or sexual relationships – intended to arouse similar feelings in readers, in contrast to erotica, which focuses more specifically on sexual feelings. Other common elements are satire and social criticism. Much erotic literature features erotic art, illustrating the text.
Despite cultural disapproval of such material, the circulation of erotic literature was not seen as a major problem before the invention of printing, as the costs of producing individual manuscripts limited distribution to a very small group of wealthy and literate readers. The invention of printing, in the 15th century, brought with it both a greater market and increasing restrictions, including censorship and legal restraints on publication on the grounds of obscenity. Because of this, much of the production of this type of material became clandestine. from Wikipedia.