Mark Addison was born on August 29, 1960. He was last seen in San Luis Obispo on September 4, 1982.
Investigators said he had made comments about wanting to live off the land in the mountains and bought camping gear prior to his disappearance.
A few days after Addison was reported missing, the vehicle he was associated with was found in the Bakersfield area.
At the time of his disappearance, Addison was described as 5'9" tall and 165 pounds, with brown hair and brown eyes. He was missing the tip of his middle finger on his left hand.
California Dept. of Justice Missing Person Search