Pseudonym adopted by a member of Martin Lloyd's race. "Dr. Peter Tanner" was the person primarily responsible for maintaining Martin's altered state of mind -- causing him to forget his true identity.
Tanner leads a small group of men, with whom he and Martin once served as soldiers in their planet's military. When the Goa'uld invaded their world they were sent out to the stars to seek allies. They found Earth, only to realize the people there were not advanced enough to help them. Tanner and the others then chose to desert and hide out here. They believed that they would surely die if they returned home, and so they drugged Martin to block his memories of his true identity -- so that he would not expose them.
Tanner operated as a psychiatrist in Montana, covertly observing Martin under the guise of treating him, and so surreptitiously helped Martin to maintain his false memories. But after SG-1 exposed him Tanner and his group went into hiding, and were staunchly pursued by the N.I.D.
They finally decided to leave Earth when their ship returned to orbit on an automated timer.
Point of No Return - Tanner's covert cover as a psychiatric physician is exposed when SG-1 investigates Tanner's "patient," Martin Lloyd.
Wormhole X-Treme! - Tanner and his men leave Earth aboard their advanced space vessel, having narrowly avoided capture by the N.I.D.