I decided to pick this up and give it a whirl after reading the recent biography of Warren Buffett, The Snowball.
Buffett was a big fan of the book. It left a lasting impression of me. It's almost a philosphical book about the importance of self-control and being thoughtful enough to think of the other person.
In a somewhat dubious application of these virtues, Carnegie primarily suggests applying these values to business situations. In short, you can make a lot more money by focusing on good customer service.
However, the lay person who wants to get along hassle free in life can pick up many valuable tips from this book.
Read my Suite101 review here.