Understanding the Benefits of Transcendental Meditation
Transcendental Meditation Technique – A Complete Introduction
TM is not a religion, philosophy nor a belief system.
TM has its origins in a 5,000 year old tradition called the Vedic tradition - so basically, I can't give you a firm answer on the first person to ever practice it. That being said, the tradition was revived in modern times by Maharishi Mahesh Yogi and has been taught, systematically, by highly trained teachers ever since.