F.M. Alexander (1869—1955) was an actor who lost his voice while performing. Doctors and vocal coaches could not help him, but when he experimented to find the cause, he discovered it was something he was doing by himself to himself that interfered with his natural coordination, and thus how he used his voice. He discovered certain axioms about human movement and structure, and using these facts derived two important principles for how to use this information.
When he consistently applied these principles, he recovered his voice, improved his overall coordination and general way of moving, and improved his health. The technique he developed on his way to improving his voice is now called the Alexander Technique.