For about the first fifty pages of so of Lloyd Shepherd's The English Monster; or, The Melancholy Transactions of William Ablass (Washington Square Press, 2012), I wasn't at all sure the novel was going to work. Chapters alternate between 1811 London at the time of the Ratcliffe Highway murders and the 1560s high seas as a young man accompanies John Hawkins on a slaving voyage; just whether/how the two were going to converge was entirely unclear, and confusing. But things gradually became clear, in a way that I can't explain without giving away the game, so you'll have to go read the book yourself. Suffice it to say, I'm very glad I kept reading.
While the shifting perspectives in the book remained a bit disconcerting throughout, and there were some rough patches that might have benefited from a bit more of an edit, overall the book proved a good read.