Many things in the book I could totally agree with. He talks about hard mountain climbing like it is a war instead of a romantic Hemingway book. However, he also talks about a lot of stuff that made me think he's crazy. He did a lot of hard free soloing when he was younger, and that's a sure way to get yourself killed. He talks about some of his friends and climbing partners that died in the mountains, around 40 total. He also seemed to harbor a lot of anger toward people that did less committing sports like sport climbing and people that were content to climb established routes instead of make their own. Personally I'm happy just to see people out there enjoying the outdoors and doing something physical.
His attitudes of going hard and working for some abstract goal most people don't understand probably resonate with most climbers. However, his attitudes of hate and disgust with people who don't do his kind of climbing was elitist and harsh. Throughout the book his negative feelings did fade somewhat, which was nice.
It's a book by a climber for climbers. If my parents read Kiss or Kill they would probably be even more terrified for my life. On the other hand I think it is a very honest portrayal of hard alpine climbing and should be read by aspiring alpinists before they decide to go do hard free soloing or any hard committing routes. Up there you have to be 100%. 99% leads to very bad things happening.