This book has to be the best Western novel of all time. Forget about Riders of the Purple Sage, or Shane, or The Virginian, or Lonesome Dove. Nah, all those pale in comparison next to the magnificent glory of Hellhole.
Let's start by talking about body count, the number 1 criteria for determining the merits of a Western. Michael, Freddy and Jason would be jealous. A whopping 115 people go their just reward in this slender novel of 155 pages (I'm referring to the original 1973 version), most of them sent there by our "big man" hero O'Brien, the man with one name. That's an average of 1.3 grisly and dramatic deaths per page, assuming my BA-in-English math is right. That's impressive by anyone's standards.
The second-most important criteria for determining the merits of a Western is the shallowness of the characters. Hellhole beats them all (as does O'Brien with anyone who gets in his way, or looks at him funny, or asks if Coke is okay when he orders a Pepsi). The bad guys are thoroughly bad because they're bad guys and O'Brien is thoroughly good because he's the good guy. The bad guys engage in bad-guy activities like "grinning evilly" and "giving an evil laugh". The good guy does good-guy things like sticking up for the little people and stopping to give murdered folks a decent burial and beating the holy living hell out thieving mule skinners and sadistic prison wardens. He also does a lot of growling.
Finally, Hellhole exceeds another important criteria, in that every woman must be a buxom prostitute with a heart of gold or a long-suffering pioneer wife with a heart of gold. Instead, Hellhole goes one step farther and features virtually no female characters at all. The most prominent one exists only to die and she doesn't make it out of chapter 1 (see body count criteria above). The second-most prominent appears at the very end. She's a small-town girl who invites O'Brien to her home so her dad can dig the slug out of his shoulder left there by a very bad guy. Her motivation in doing this, presumably, is because O'Brien is just so damn sexy.
I think you'll agree with me that that Hellhole is indeed the greatest Western novel ever written by anyone at any time and that will never be surpassed by anyone at any future time. On this there can be no debate.