I'm a little late to this story, but I want to give a shout out to Malcom Jones' well-observed Newsweek piece on literary writers who "go slumming" by writing detective novels. This summer, it's been Denis Johnson and Thomas Pynchon who have tried on trenchcoats, but Jones notes that some of America's canonical authors (Faulkner, Dreiser) have dabbled in noir over the years. What these literary authors discovered, says Jones, is that writing an exceptional mystery is no easy task:
So what happens when mainstream novelists tackle noir? More often than not, they find it's harder than it looks. Mailer's Tough Guys Don't Dance contains some brilliant passages, but mostly it's a mess (paradoxically, when Mailer took on real crime in The Executioner's Song, he wrote arguably his best book). McCarthy's No Country for Old Men is also occasionally wonderful, but it might be his worst novel—who would have thought that we would ever accuse him of sounding preachy?
I agree with Jones about Mailer but not about McCarthy. That said, I read No Country for Old Men after seeing the film, and I think the book probably benefited from the vivid memory of Javier Bardem's perfectly rendered Anton Chigurh.