I was required to purchase this for a college class. Amazon had a great price and shipping was fast.However, the book itself is useless. $100 gets you a text that tells you basic things you already know. If you know nothing about a healthy lifestyle, a search of the internet will give you much better information for free. There is absolutely no reason to buy this book unless it is required. If you have a class for which it is required, I suggest you drop the class.