1. The problem statement, all variables and given/known data Forces involved when a book is resting on top of a table. 2. Relevant equations F = ma 3. The attempt at a solution This is not really a homework question but it is from school. I found a previous thread (https://www.physicsforums.com/threads/misinterpretation-of-newtons-third-law.526181/). After reading this a few times it seems to make perfect sense to me. The weight force happens to be the same as the normal force the book exerts on the table but they are not an interaction pair. However, I was reading through one of my old GCSE revision guides for physics. I'm British and GCSE are the main exams you sit before going to college (ages 15-16). If I have understood the attached post then this revision guide is completely incorrect. I have attached the page from the book which is titled "Newton's 3rd Law" and it says in capital letters at the bottom in a bright red box that the reaction force is equal and opposite to the weight! This is a mainstream revision guide available from amazon. Have a missed something or is this completely wrong? It also says before the statement, learn this very important FACT.