It's no secret that we like to poke fun at the fast-talking sales influencers and self-styled sales gurus that clog up our news feeds with their half-baked advice. But long before social media (or the internet, for that matter), Dale Carnegie pioneered the art of the self-help and salesmanship seminar, culminating in the publishing of his most famous book, How to Win Friends and Influence People, which, still to this day, makes nearly every list of recommended sales books in the world.