I really enjoyed "No More Mr. Nice Guy" by Dr. Glover, it does a really good job of covering this very topic and providing the reader with a plan for how to fix the situation.
It isn't some strange P.U.A. take on the "friendzone" issue, either. I think a lot of people are turned away from the book because of its title and connotations. I think that was a clever move on the author's point, to be honest.
So from what I understand, it's more of a self-help/self-confidence book than anything.
Also perspective is different for people in healthy relationship. We don't have a word friendzone mean anything.