Story 1: The True Identity of Starfinger!
Starfinger begins to destroy the Great Wonders of the 30th Century until he is delivered the mineral called rejuvium. The Legion of Super-Heroes try to stop him, but are foiled at most of their attempts. Eventually it is revealed that Starfinger is actually Lightning Lad, under the influence of hypnotism by his doctor, Dr. Hanscom. Dr. Hanscom wanted the rejuvium and created the persona of Starfinger to steal it, but he didn't have any real powers. When his patient was the Legionnaire known as Lightning Lad, he hypnotized and used him to do all his dirty work. The real Starfinger was stopped and the rejuvium was safe.
Story 2: The Sixth Clark Kent
Superboy helps look for another Clark Kent who was named heir to a fortune.
Reprinted from Superboy (DC, 1949 series) #54