To Sell Is Human - Daniel H Pink
This book is a must read for anyone who does work as a salesperson, or anyone who has to convince, persuade, or move people as a part of their life. Which is pretty much everyone.
Daniel uses much research to challenge traditional attitudes to sales, and provides new approaches to sales and selling that are much more effective in the current marketplace. He describes the fact that there is no longer information asymmetry (where the seller knows more than the buyer) because of the free-flowing nature of information in the world we now live in.
This book also provides a myriad of sales and selling tips which will help you to sell what you sell, or to otherwise convince people to do what you want them to do, and not just to force them. This book will help you to bring people on board, to want to do what you want them to do.
I highly recommend reading this book, it will change the way you work.