Over time I've found out that there are several books written about death metal, looking at it as a social phenomenon. Such as:
- Natalie J. Purcell "Death Metal Music: The Passion and Politics of a Subculture"
- Albert Mudrian "Choosing Death: The Improbable History of Death Metal & Grindcore"
- Keith Kahn-Harris "Extreme Metal: Music and Culture on the Edge"
- Jack Harrell "The Poetics of Destruction: Death Metal Rock"
I'm actually interested how good are those, and what view on Death Metal they provide. Maybe there are also other books on the subject which I don't know about.

And of course there is "Swedish Death Metal" book by Daniel Ekeroth, but this one mostly focuses on history of some bands in the genre AFAIK, which is interesting, but in other way.

So, have anyone ever seen/read any of those? What's your opinion?

I have not read any of these. I have read Ekeroth's book as well as Costantini's 'Encyclopedia Of Dodsmetall" though but I don't care about these books, I only enjoy death metal as a music.