The Last Dickens, by Matthew Pearl (TPB, 2009, $1.50)
"Boston, 1870.
When news of Charles Dickens's sudden death reaches his struggling American publisher, James Osgood sends his trusted clerk, Daniel Sand, to await the arrival of Dicken's unfinished final manuscript. But Daniel never returns, and when his body is discovered by the docks, Osgood must embark on a quest to find the missing end to the novel and unmask the killer. With Daniel's sister Rebecca at his side, Osgood races the clock through a dangerous web of opium dens, sadistic thugs, and literary lions to solve a genius's last mystery and save his own life- and the life of the woman he loves."
Dickens' death was real. His unfinished serial The Mystery of Edwin Drood was real.
This book, The Last Dickens, though, is not, but Matthew Pearl's writing and research into the period makes it feel real. You can find this book in the mystery section.