Barton gives a group of lectures based on this book. Go to the Perimeter Institute and you can find his lectures. I have taken courses in OFT, General Relativity and String theory. This book is great for learning String Theory and is one of the best.<br>I want to talk about something else this book does. The reason I said what courses I have taken, is this book has one other consequence. It refines the skills you already have. Had I read this book first before OFT I would have really been ahead of the game. The people I know who read this book first had a much easier time with OFT.<br><br>He does the action integrals without the Euler-Lagrange equation. Any time a book refines your skills beyond the subject it is teaching, is a really good book. Others have pointed out how good it is at teaching string theory. I just wanted to point out other benefits of the book.<br><br>Even if string theory turns out to be wrong, this book will make you a better Physicist. Remember to go online and watch some of his lectures. His lectures make reading the book boring, because you feel you have seen it all before and that is good.