The great psychologist Dr. Albert Ellis recently died at 93 years of age. He invented an early ( and I believe more powerful ) form of cognitive therapy back in the 1950s called REBT – Rational Emotive Behavioral Therapy.
For therapeutic use or personal development I think REBT is one of the most powerful “philosophies” ever developed.
For a well written and short overview of what REBT is see this great essay by Waye Froggart:
While googling around I discovered that the New York Times did an article about Dr. Ellis shortly after his death: