This document summarizes key rules from the book "Brain Rules" by Dr. John Medina about how the brain works. It discusses 12 rules, but focuses on three in more depth: Exercise boosts brain power, Vision trumps all other senses, and We don't pay attention to boring things. The rules are supported by explanations of how physical activity, visual learning, emotions, and interruptions impact attention and memory in the brain. The presentation aims to provide useful information to understand brain development and function.