Maturin's writings fall into three periods. Of his three early novels, The Fatal Revenge or The Family of Montorio (1807), The Wild Irish Boy (1808) and The Milesian Chief (1812), the first only is a tale of horror. The Wild Irish Boy is a domestic story, and forms a suitable companion for Lady Morgan's Wild Irish Girl. The Milesian Chief is a historical novel, and is now chiefly remembered on account of the likeness of the opening chapters to Scott's Bride of Lammermoor (1819). After the publication of these novels, Maturin turned his attention to the stage. His first tragedy, Bertram (1816), received the encouragement of Scott and Byron. The character of Bertram is modelled on that of Schiller's robber-chief, Karl von Moor, who captivated the imagination of Coleridge himself, and who is reflected in Osorio and perhaps in Mrs. Radcliffe's villains. The action of the melodrama moves swiftly, and abounds in the "moving situations" Maturin loved to handle. Bertram was succeeded in 1817 by Manuel, and in 1819 by Fredolfo. Meanwhile Maturin had returned to novel-writing. Women, or Pour et Contre, with its lifelike sketches of Puritanical society and clever characterisation, appeared in 1818, and was favourably reviewed by Scott.[59] Melmoth the Wanderer, Maturin's masterpiece, was published in 1820, and was succeeded in 1824 by his last work, The Albigenses, a historical romance, following Scott's design rather than that of Mrs. Radcliffe.

In reviewing The Family of Montorio, Scott prudently attempted only a brief survey of the plot, and forsook Maturin's sequence of events. In his sketch the outline of the story is comparatively clear. In the novel itself we wander, bewildered, baffled and distracted through labyrinthine mazes. No Ariadne awaits on the threshold with the magic ball of twine to guide us through the complicated windings. We stumble along blind alleys desperately retracing our weary steps, and, after stumbling alone and unaided to the very end, reach the darkly concealed clue when it has ceased to be either of use or of interest to us. Many an adventurer must have lain down, dispirited and exhausted, without ever reaching his distant and elusive goal. Disentangled and simplified almost beyond recognition, the story runs thus: In 1670, Count Orazio and his younger brother are the sole representatives of the family of Montorio. Orazio has married Erminia di Vivaldi, whom he loves devotedly. She does not return his love. The younger brother determines to take advantage of this circumstance to gain the title and estates for himself, and succeeds in arousing Orazio's jealousy against a young officer, Verdoni, to whom Erminia had formerly been deeply attached. In a violent passion Orazio slays Verdoni before the eyes of Erminia, who falls dead at his feet. This part of his design accomplished, the younger brother plots to murder Orazio himself, who, however, discovers the innocence of his wife and the hideous perfidy of his brother. Temporarily bereft of reason, Orazio sojourns alone on a desert island. When his senses are restored, he resolves to devote the rest of his life to vengeance. For fifteen years he buries himself in occult studies, and when his diabolical schemes have matured, returns, disguised as the monk Schemoli, to the scene of the murder. He becomes confessor to his brother, who has assumed the title and estates. It is his intention to compel the Count's sons, Annibal and Ippolito, to murder their father. Death at the hands of parricides seems to him the only appropriate catastrophe for the Count's career of infamy. To reconcile the two victims—Annibal and Ippolito—to their task, he "relies mainly on the doctrine of fatalism." The most complex and ingenious "machinery" is used to work upon their superstitious feelings. No device is too tortuous if it aid his purpose. Even the pressure of the Inquisition is brought to bear on one of the brothers. Each, after protracted agony, submits to his destiny, and the swords of the two brothers meet in the Count's body. When the murder is safely accomplished, it is proved that Annibal and Ippolito are the sons, not of the Count, but of Schemoli and Erminia. By the irony of fate the knowledge comes too late for Schemoli to save his children from the crime. At the close of a lengthy trial the two brothers are released, but deprived of their lands. Ultimately they die fighting in the siege of Barcelona. Schemoli perishes, in the approved Gothic manner, by self-administered poison. Intertwined with the main theme of Schemoli's fatal revenge are the love-stories of the two brothers. Rosolia, a nun, who seems to have been acquainted with Shakespeare's comedies, disguises herself as a page, and devotes her life to the service of Ippolito and to the composition of sentimental verses. She only reveals her sex just before her death, though we have guessed it from her first appearance. Ildefonsa, who is beloved of Annibal, has been forced into a convent against her will—a fate almost inevitable in the realm of Gothic romance. When letters are received authorising her release from the vows, a pitiless mother-superior reports that she is dead. She is immured, but an earthquake sets her free, for Maturin will move heaven and earth to effect his purposes. The ill-fated maiden dies shortly afterwards. Ere the close it proves that Ildefonsa was the daughter of Erminia, who had been secretly married to Verdoni before her union with Orazio. Such is the skeleton of Maturin's story, when its scattered members have been patiently collected and fitted together. The impressive figure of Schemoli, with his unholy power of fascinating his reluctant accomplices, lends to the book the only sort of unity it possesses. But even he fails to arouse a sense of fear strong enough to fix our attention to so wandering a story. Like the doomed brothers, we drift dejectedly through inexplicable terrors, and we re-echo with fervour Annibal's dolorous cry:

"Why should I be shut up in this house of horrors to deal with spirits and damned things and the secrets of the infernal world while there are so many paths open to pleasure, the varieties of human intercourse and the enjoyment of life?"

Maturin, a disciple of Mrs. Radcliffe, feels it his duty to explain away the apparently miraculous incidents in his story, but he lacks the persevering ingenuity that partly compensates for her frauds. On a single page he calmly discloses secrets which have harassed us for four volumes, and his long-deferred explanations are paltry and incredible. The bleeding figures that wrought so painfully on the sensitive nerves of Ippolito are merely waxen images that spout blood automatically. Disappearances and reappearances, which seemed supernatural, are simply effected by private exits and entrances. Other startling phenomena are accounted for in the same trivial fashion.

Maturin seems to have crowded into his story nearly every character and incident that had been employed in earlier Gothic romances. Schemoli is a remarkably faithful portrait of Mrs. Radcliffe's Schedoni. From beneath his cowl flash the piercing eyes, whose very glance will daunt the bravest heart; his sallow visage is furrowed with the traces of bygone passions; he shuns society, and is dreaded by his associates. The oppressed maiden, driven into a nunnery, drugged and immured, the ambitious countess, the devoted, loquacious servant, the inhuman abbess—all play their accustomed parts. The background shifts from the robber's den to the ruined chapel, from the castle vault to the dungeon of the Inquisition, each scene being admirably suited to the situation contrived, or the emotion displayed. Maturin had accurately inspected the passages and trap-doors of Otranto. No item, not a rusty lock, not a creaking hinge, had escaped his vigilant eye. He knew intimately every nook and cranny of Mrs. Radcliffe's Gothic abbeys. He had viewed with trepidation their blood-stained floors, their skeletons and corpses, and had carefully calculated the psychological effect of these properties. He had gazed with starting eye on the lurid horrors of "Monk" Lewis, and had carried away impressions so distinct that he, perhaps unwittingly, transferred them to the pages of his own story. But Maturin's reading was not strictly confined to the school of terror. He had studied Shakespeare's tragedies, and these may have suggested to him the idea of enhancing the interest of his story by dissecting human motive and describing passionate feeling. In depicting the remorse of the count and his wife Zenobia, who had committed a murder to gratify their ambition, and who are tormented by ugly dreams, Maturin inevitably draws from Macbeth. Zenobia, the stronger character, reviles her husband for indulging in sickly fancies and strives to embolden him:

"Like a child you run from a mask you have yourself painted."

He replies in a free paraphrase of Hamlet:

"It is this cursed domestic sensibility of guilt that makes
cowards
of us all."

Maturin is distinguished from the incompetent horde of romance-writers, whom Scott condemned, by the powerful eloquence of his style and by his ability to analyse emotion, to write as if he himself were swayed by the feeling he describes. His insane extravagances have at least the virtue that they come flaming hot from an excited imagination. The passage quoted by Scott—Orazio's attempt to depict his state of mind after he had heard of his brother's perfidy—may serve to illustrate the force and vigour of his language:

"Oh! that midnight darkness of the soul in which it seeks for something whose loss has carried away every sense but one of utter and desolate deprivation; in which it traverses leagues in motion and worlds in thought without consciousness of relief, yet with a dread of pausing. I had nothing to seek, nothing to recover; the whole world could not restore me an atom, could not show me again a glimpse of what I had been or lost, yet I rushed on as if the next step would reach shelter and peace."