Dale Carnegie (Maryville, MO, 1888 – New York, 1955) was an American writer and lecturer. He developed the famous courses in self-improvement, salesmanship, corporate training, public speaking, and interpersonal skills. Carnegie founded in 1912 the Dale Carnegie Institute to train people in success.
Dale Carnegie wrote: "Public Speaking and Influencing Men of Business" in 1913, "Art of Public Speaking" with Joseph Berg Esenwein in 1915, "Public Speaking" in 1920, "How to Win Friends and Influence People" in 1936, a bestseller that remains popular today. He also wrote "How to Stop Worrying and Start Living" in 1948, "Lincoln the Unknown" in 1932, among other books. Carnegie also wrote biographies, motivated by his belief that the best way to learn the secrets of success was to read up on history's most successful people. 
Dale Carnegie Training sells those books and teaches those courses promising to bring you out of your shell. . . speak better . . . listen better . . . be a better person . . . and persuade OTHER people to do what you want. 
It is the way we react to circumstances that determines our feelings.
Many people think that if they were only in some other place, or had some other job, they would be happy. Well, that is doubtful. So get as much happiness out of what you are doing as you can and don't put off being happy until some future date.
When dealing with people, let us remember we are not dealing with creatures of logic. We are dealing with creatures of emotion, creatures bustling with prejudices and motivated by pride and vanity.
You can make more friends in two months by becoming interested in other people than you can in two years by trying to get other people interested in you.
Forget yourself; do things for others.
Cooperate with the inevitable.