Dale Carnegie
The late Dale Carnegie was a lecturer, communications consultant, and best-selling author. He developed courses in self-improvement, public speaking, and interpersonal skills. Early on in his career, he realized that people needed guidance on dealing with fellow human beings, and since little had been written on the subject at the time, he decided to write his own book that he could use in his courses. With over 15 million copies sold, How to Win Friends & Influence People (first published in 1936) is now considered the definitive self-help book.