I normally don't write reviews, but after reading the shockingly cynical comments I had to add my 2 cents.
This book is great for people who have trouble communicating, it gives valuable tips for improving self confidence when speaking, initiating conversation, remembering names and getting buy in.
While it is meant primarily to help in business relationships, I found it has been helpful in my personal life. A normally shy person, the book has helped me start conversations and meet new people. Speaking in terms of people's interests is about getting that conversation started, not about faking an interest and pretending to have the same interests.
Even though the book is titled "How to win friends .." the purpose of the book is not to literally win you friends, it's about improving communication, sales and presentation skills. There is nothing ground breaking in this book and in fact all the principles are simply principles of common sense but it helps you put them into action day-to-day.
I highly recommend this book for people who need help breaking out of their shell, for people who work in sales or give presentations, or for anyone who wants to move up in their job.