I must warn you: it's not an easy read. I've been studying it for years, so that I can absorb some of its spirit (and some thoughts) into my Tyr characterization, but still have to re-read every sentence at least three times before I got to the actual meaning. But it's well worth the effort.

The other excellent source of Niet fandom is Kit Manson's story, "The Recreation of the Warrior". It's a little less bloodthirsty than KHC'S essays, and the good stuff (=cultural background) is scattered all over the story, but I still recommend it.