I would make everyone read a beginning to the English language because English is probably the most spoken language, everywhere you go you probably will find someone who speaks English. If this would be a book that everyone would read then no matter where you go you can speak with anyone. This would change the world by making traveling to countries where your language isn't spoken making it so much more easy to get directions if you're lost, to find someplace to eat, and basic info if everyone would know how to talk in basic English.