Head on over to Grantland and check out their Errol Morris week. And while you're at it, dig Brin-Jonathan Butler's excellent Kindle Singles interview with Morris:
BJB: Did In Cold Blood have as big an impact on you as watching Psycho for the first time?
EM: I think … it was first published in 1966. The murders occurred in 1959. I remember reading it when it was serialized in The New Yorker in 1965. That was the year that I started at Wisconsin. I went on a Dreiser kick a while back, around the time I was making Tabloid. I'd never read An American Tragedy. I thought it was … unbelievable. I started reading more and more. American Tragedy is a masterpiece. There was something that Dreiser did, and Capote had to be really aware of Dreiser; it's hard not to be. It's that at the heart of these stories there was something deeply arcane. If Dreiser was struggling to try to capture kind of, I dunno, economic determination, materialism. There are these moments in American Tragedy, where it's at that moment of the murder, where he can't grab onto it. It becomes almost impenetrable. I remember, it must have been 1965, reading about Perry and Hickock approaching the Clutter house in Kansas. I should find the actual sentence where Capote says that "The sequence of events that followed would ultimately take the lives of six people." I remember reading it and thinking this is Greek Tragedy. A kind of inevitability—there's a certain kind of inevitability I feel in Dreiser too—but a certain inevitability I feel in Capote of a juggernaut to nowhere. Maybe it's one of the reason I love Detour so much. Of being in the grip of strange forces.
For just a buck, it's a great read.