Some twentieth-century authors who have written novels that comment upon and challenge Victorian classics do so, like Jean Rhys and Peter Carey, by shifting the point of view from which we follow the action or by rewriting one of the characters. Thus, Rhys makes Brontë's Bertha the center of her novel while Carey makes the escaped convict the center of his. Other writers who create revisionist narratives, like Graham Swift in Waterland, create elaborate parallels with the characters and actions of the earlier text, but do not so obviously play with an alternate narrative. Peter Carey takes a third tack, for he not only puts Dickens's characters into his novel but he also inserts the novelist himself -- or someone who stands in for him -- in the action. As Thomas Mallon points out,
Tobias Oates is really Charles Dickens. A young writer ambitious to surpass Thackeray in reputation, Oates is the author of a highly successful comic novel, Captain Crumley -- i.e., The Pickwick Papers. Up from proverty; a crusader in the press against injuustice; better at dealing with humanity in its abstract than in its individual forms; a devotee of amateur theatricals; peculiarly close to his sister-in-law: It's all there. All right, Dickens probably never slept with Mary Hogarth, as Oates does with Lizzie, but he was wildly devoted to her, and shattered by her death in 1837 -- the year in which Jack Maggs takes place, and one year before Dickens attended Professor John Elliotson's animal-magnetism demonstrations.
In a book on the subject, Dickens and Mesmerism, Fred Kaplan points out the phenomenon's effect on any number of Dickens novels (including Oliver Twist and Great Expectations). 
Carey's Jack Maggs does not, however, exactly parallel Dickens's life in matters other than his relation to his sister-in-law. What changes does Carey make, for example, in the novelist's father? his childhood?
Mallon, Thomas. "Writing Like the Dickens." GQ. (March 1998): 167-69.
Last modified 25 January 2004