Speed Racer - Who is Racer X ?

Can't quite figure it out. Very, very vague description of the guy in all of the episodes. They never describe who the guy is? Comments turned off by TH-cam. Sad!
© Speed Racer Enterprises, Inc. (1966)
Creator: Tatsuo Yoshida
Voices: Peter Fernandez, Corinne Orr, Jack Grimes, Jack Curtis