I quite liked the book. It's well written because it lacks voyeurism, provides enough space for the victims and accomplishes to give an understanding why people become murder.
BUT, after finishing I read that witnesses were misquoted by Capote and what is even worse, entire events were made up. So it's fiction and not non-fiction as it claims. Therefore only 2 of 5 from me.

Nevertheless, Capote spent six years of work on this novel, spoke a lot with the murderers and many wittnesses. So I assume many things are accurate and hold the earlier mentioned premise. There were many things I found interesting in the novel. For example it showed that even in the 60s there was some awareness of how early childhood trauma affects the life of people. I honestly did not expect that. Next, the process, if it really happened as it is described in the book, was really kafkaesque. The death penalty seemed to be decided before it even started. The psychiatrist who prepared a report about their mental state was only able to answer with 'yes' or 'no'. Yeah ok... Why does any trial of the US feel like a complete sh*tshow all the time?
Other things that stuck out to me were the completely randomness of the murder. It seemed like a bad coincidence and absurd. I got the feeling if they hadn't murdered the Clutters, maybe it would have been another group of people on another random day. And last thing is that this felt like a true crime series from Netflix, a genre which Capote had somehow innovated/made popular with this book.