In my childhood Richard Carlson was perhaps my favorite actor because of his many appearances in '50s sci-fi movies (Magnetic Monster, It Came from Outer Space, Creature from the Black Lagoon, etc.). In these and similar movies he consistently portrayed a model of calm, intelligent, thoughtful bravery in the face of strange new dangers, and he continued in this vein in the TV series "I Led Three Lives".
As a child I had no reason to disbelieve the show's portrayals of subversive Communist activities in the United States. Later I read Herbert Philbrick's book that served as the source of the name and background for the series, and it too had the ring of truth.
Yet as other comments here about this show reveal, the idea that America was the target of conspiracy and espionage is derided as paranoid. The investigations of the House Un-American Activities Committee are described as a witch hunt, on the implicit premise that since there are no witches, there must not have been Communists either. We still hear laments for the Hollywood writers, directors, etc., who found it difficult to find work after being blacklisted for refusing to admit to their membership in the Communist Party.
Well, folks, the cat is out of the bag. As if the world was not already full of enough evidence of the evil of Communism, the fall of the Soviet Union led to the opening of the KGB archives in Moscow to researchers, and guess what... At the direction of the Soviet Union, there were Communist agents and sympathizers in the US Army, the Manhattan Project, the State Department, many labor unions, and other strategic targets. The archives show that the Communist Party USA received millions of dollars each year from the Soviet Union for purposes of undermining America, with Hollywood being specifically targeted for infiltration.
In that atmosphere I think it is remarkable that "I Led Three Lives" ever got produced. I whole-heartedly hope that this show does get re-released. However much it may have been dramatized, "I Led Three Lives" shows how America was in fact endangered by its enemies, foreign and domestic.