Not Quite Dead — John MacLachlan Gray

On a rust-bucket cargo ship bound from Liverpool to the United States in 1848, an Irish stowaway named Devlin steals a suspicious package after witnessing it changing hands between two sea captains. All he finds is a seemingly worthless pile of papers marked "David Copperfield, Final Four Numbers, by Charles Dickens." Devlin is determined to see if he can somehow turn events to his advantage by paying a call on Dickens's American publisher.
A year later, a newly admitted patient to a Baltimore hospital, a disreputable writer who goes by the name of Edgar Allan Poe, is clearly raving mad, which makes it easy to dismiss his claims to have information about the murder of an innocent woman.
Meanwhile, the eminent English novelist Charles Dickens has embarked on a tour of America, where his views are not received as he would have wished. Dickens's growing discomfort reaches new heights of intensity when he finds himself sharing disreputable lodgings---and reluctantly collaborating with---none other than Edgar Allan Poe, who has gone into hiding after faking his own death in a desperate attempt to escape the Irish mob.
Like White Stone Day, which The Washington Post hailed as "a Dickens of a thriller," this is a brilliantly imaginative tale in which crime and literature intersect in surprising ways.