Dale Carnegie's self-help bestseller, How to Win Friends and Influence People, was published in 1936. The book outlines several ways to become a likeable person, manage your relationships better, make a great impression to win over others and even make them change their behaviour for you. At the core, Dale Carnegie's idea is that other people's behaviour can be changed by modifying your own. The book is amongst the best-selling of all time, with millions of copies sold worldwide.