Mandino became a motivation speaker after turning his life around during a very difficult time in his life. He was a bomber pilot in WWII but a salesman afterwards. He eventually became an alcoholic, who was unable to sustain a job. This lead to his wife taking his child and leaving him. Mandino decided to end his existence, but he looked through some self-help books before hand and changing his mind.
Some of his works are:
The Greatest Salesman in the World The Twelfth Angel The Greatest Miracle in World The Choice