The Difference by Charles Willeford
A quick plot summary for those curious about such things: a young man is swindled out of his inheritance and seeks retribution and justice whilst coming of age. But all is not as it seems. Johnny Shaw is a grasping, devious git, with little concept of honour and quite willing to shoot a man in the back. Willeford has exposed the myth of the noble cowpoke as just that - a myth - and this is what makes this such a great, if quick, read. Shaw enjoys watching his skin harden as he makes the transformation from wronged citizen to outlaw, taking pleasure in the killing of his enemies and, in the denouement, creating his own legend as lethal hired gun. That he doesn't succeed in killing all those who "wronged" him is not down to lack of desire or ability, rather disgust that they are not worth killing in the end.
Willeford's pen has created a character who, although sympathetic to start with, by the end of the novel is not truly worthy of sympathy. Lacking mercy, honour and morals, Shaw is nonetheless an intriguing character, and this is Willeford's triumph.