We publish this letter from Aldrich H. Ames with mixed feelings and only because Ames indeed is an expert, of sorts, on polygraphs. Ames is a convicted spy. He was a CIA employee for thirty-one years who volunteered his services to the KGB in 1985. During the following nine years until his arrest in February 1994 he compromised more than 100 intelligence operations against the Soviet Union. He successfully passed counterintelligence polygraph examinations. Ames mailed this letter to the editor, handwritten, from Allenwood federal penitentiary--EDITOR