On books about interpersonal communication and influence

I read somewhere the opinion that there are only two books in interpersonal communication, negotiation, and so forth that have ever been written. And that all other books are just re-treads of the same two.

The argument was that EVERYTHING is either a re-tread of Dale Carnagie's How to Make Friends and Influence People or Machiavelli's The Prince. Or both.

But that, if you've read both of those, you've pretty much covered Getting to Yes, What They Don't Teach You In Harvard Business School, The Games People Play, and everything else in the genre.

Anyone wanna sanity-check a physics idea my father has?

My dad's an amateur astrophysicist, and has been tinkering with a little bit of the math on red shift and the "missing mass" problem. He just emailed me a couple of his notes, and was wondering if I knew anyone who could sanity-check his math, see if there's anything in it, or if it's something someone else has already worked on. Anyone want me to forward it to them to check through it?

(I don't have the background, myself. I can more-or-less FOLLOW his argument, when reading it written out in the notes, but I have neither the background in the theory, or the skills in the math to have a clue whether it's true or not.)