“The key to successful leadership is influence, not authority.”
~ Ken Blanchard
Of course, there are different ways to analyse and understand the quote.
However, one has to admit that being able to influence and persuade others is one of the most important skills in business and life. And even if you are sceptical about the idea, I would recommend you reading the book just to know when someone tries to manipulate you.
Nobody likes being manipulated. Yet, it is happening on daily basis, even when you are walking down the street or doing grocery shopping.
“Influence: The Psychology of Persuasion” gives you a great brief of the science behind the influence and I would surely recommend you to read it.
Having said that, if there is just one book you would like to read about the subject, I would recommend more “How to Win Friends and Influence People” by Dale Carnagie.