There was a book I flipped through in a bookstore a couple of years
ago called Negotiating for Dummies. In the front it had a page that
analysed films that involved negotiation (one of the films was
Ruthless People) from a negotiator’s point of view.

I can’t find the book anymore, and I don’t really want to pay for it
anyways as it’s a bit pricey, but I’d like to know what was written on
that page.

Also, I was wondering if there were websites that had negotiating
experts analyse other, more recent films (eg. Ransom, The Negotiator)
in a similar manner. So it would evaluate the actions of the main
characters, explain why it was a good or bad negotiating move, and
show the reasoning behind it.

According to the books Table of Contents at Amazon, the chapter is:

Chapter 22:Ten Videos to Rent, Watch and Enjoy - pages 315-325