Clinch's debut novel is a solid piece of writing, a mordant, uncomfortable tale of a depraved and dangerous wretch and the havoc he wreaks on himself and those around him.
Finn is the backstory of Pap Finn, Huckleberry Finn's father, whose scant presence in Mark Twain's masterful novel reveals a repulsive and evil man whose influence on his son is the spooky music underlying the book. Clinch amplifies this character, imbuing it with a grotesque but very human sympathy, and relates it not only to the source novel, but to the society of the time, and by extension, our own.
This is not a gentle read. Not only is the principle character a man of the vilest habits and character, but so are several others in the novel, and Clinch does not spare the reader with euphemistic niceties in describing them or their depravities. Despite this, or perhaps because of it, the novel is thoroughly compelling and Clinch's prose and narrative style drive the reader hard.
The timeline of the novel is essentially the decade and a half leading up to Pap Finn's death in Huckleberry Finn. It takes as its base the curious passage in that novel, where Pap's body is discovered by Jim and Huck in an abandoned house floating in the Mississippi (although the identity of the corpse is unknown to Huck at the time).
"He went, and bent down and looked, and says: "It's a dead man. Yes, indeedy; naked, too. He's ben shot in de back. I reck'n he's ben dead two er three days. Come in, Huck, but doan' look at his face -- it's too gashly."
I didn't look at him at all. Jim throwed some old rags over him, but he needn't done it; I didn't want to see him. There was heaps of old greasy cards scattered around over the floor, and old whisky bottles, and a couple of masks made out of black cloth; and all over the walls was the ignorantest kind of words and pictures made with charcoal. There was two old dirty calico dresses, and a sun-bonnet, and some women's underclothes hanging against the wall, and some men's clothing, too. We put the lot into the canoe -- it might come good. There was a boy's old speckled straw hat on the floor; I took that, too. And there was a bottle that had had milk in it, and it had a rag stopper for a baby to suck." –The Adventures of Huckleberry Finn, Chapter 9
From this, and a few other mentions in Twain's novel, Clinch constructs his own unique view of the character of Pap Finn, and by extension of Huck. A few others of Twain's characters (Huck himself, Judge Thatcher, the Widow Douglas, and a much younger and even more corrupt King) appear briefly in the novel and several incidents are explained from a different viewpoint than Twain's naif Huck.
The book has aroused some controversy among Twain scholars for its premise that Huckleberry Finn is the product of Pap and a freed black slave called Mary and is thus a mulatto. I suspect Clinch took this idea from Twain scholar Shelly Fishkin's excellent book "Was Huck Black?" which examines published and unpublished writing by Twain with intensive biographical and historical research and insights gleaned from linguistics, literary theory, and folklore to draw the same conclusion.
In my opinion, any book that can heat up doctoral level literary scholars to the point where they are abusing each other like drunken fishwives is worth reading on that score alone, but Clinch's scalding and intriguing prose make this a book any serious reader should not miss.