According to the Oxford English Dictionary, "chapbook" is a "modern name applied by book collectors and others to . . . the popular literature . . . formerly circulated by itinerant dealers or chapmen, consisting chiefly of small pamphlets of popular tales, ballads, tracts, etc." The small size of the chapbooks, and their original paper binding (many chose to have them rebound in boards and leather, however) made them available to a wider circle of readership which could not afford the exorbitant prices of novels. The Gothic thrived in this medium.
Often condensed forms of longer novels, the chapbooks showcase such Gothic conventions as imprisonment of a maiden, the search for identity, and monstrous villains, usually either related to the heroine or members of the Catholic clergy.
"We strolled through a variety of castles, each of which was regularly called Il Castello; met with as many captains of condotteri, heard various ejaculations of Santa Maria and Diablo; read by a decaying lamp and in a tapestried chamber dozens of legends as stupid as the main history; examined such suites of deserted apartments as might set up a reasonable barrack, and saw as many glimmering lights as would make a respectable illumination." -Sir Walter Scott

Horrible Revenge; or the Monster of Italy! A Romance of the Sixteenth Century. Also, Hopeless Love, an Interesting Tale. By Issac Crookenden. London: R. Harrild, 1808. 

Horrible Revenge; or the Monster of Italy! A Romance of the Sixteenth Century. Also, Hopeless Love, an Interesting Tale. By Issac Crookenden. London: R. Harrild, 1808. The Sadleir-Black Collection of Gothic Novels. Chapbooks could barely be issued quickly enough to meet consumer demand. Their cheap binding and small size made them more affordable to the average reader. Here, the murdered father confronts his son. Note the hand-colored engraving. Issac Crookenden has been called the "great counterfeiter" of chapbooks because of the sheer volume of his output and his habit of plagiarizing the autors of full-length Gothic novels. Here, the monstrous Julien strives to seduce his sister, the matchless Amanda. 

Douglas Castle; or the Cell of Mystery. A Scottish Tale. By C F Barrett. London: A Neil, 1803. Second edition. The Sadleir-Black Collection of Gothic Novels.

Douglas Castle; or the Cell of Mystery. A Scottish Tale. By C F Barrett. London: A Neil, 1803. Second edition. The Sadleir-Black Collection of Gothic Novels. This tale is a condensation of Clara Reeve's The Old English Baron. Here, the evil Baron Douglas terrorizes both his wife and daughter, imprisoning them in an iron tower. They are rescued by his daughter's secret lover, who by the aid of supernatural forces discovers the secret of his identity, enabling him to vanquish the Baron. 

Fatal Secrets; or, Etherlinda de Salmoni. A Sicilian Story. By Issac Crookenden. London: J. Lee, 1806. The Sadleir-Black Collection of Gothic Novels.

Fatal Secrets; or, Etherlinda de Salmoni. A Sicilian Story. By Issac Crookenden. London: J. Lee, 1806. The Sadleir-Black Collection of Gothic Novels. Richard Beraldi, the villain of the tale, is guilty of kidnapping, adultery, murder, and a last, almost superfluous, fatal secret: incest. 

Spectre of the Turret; or Guolto Castle. A Romance. By Issac Crookenden. London: R Harrild, nd. The Sadleir-Black Collection of Gothic Novels.

Spectre of the Turret; or Guolto Castle. A Romance. By Issac Crookenden. London: R Harrild, nd. The Sadleir-Black Collection of Gothic Novels. Here, Crookenden not only plagiarizes Lewis's The Monk, but also Shakespeare, most notably The Winter's Tale. 

The Black Forest; or, the Cavern of Horrors. A Gothic Romance, from the German. The Sadleir-Black Collection of Gothic Novels. London: Ann Lemoine, 1802. 

The Black Forest; or, the Cavern of Horrors. A Gothic Romance, from the German. The Sadleir-Black Collection of Gothic Novels. London: Ann Lemoine, 1802.