Superman, Vol. 1

Man or Superman? - After a series of strange coincidences, including a recent problem with the subway system, Lois begins to suspect that Clark may be Superman.

The Human Bomb - A gang of crooks are willing to commit suicide, killing innocent bystanders if the people they rob fail to comply with their requests.

Muscles for Sale - A series of daring robberies are commited by people showing a much higher level of physical fitness than one would expect by looking at them. It's up to Clark Kent to go undercover.

When Titans Clash - Luthor somehow gains superpowers from at attempt to kill him with the electric chair. After tracking down the powerstone, he is soon a physical specimen far beyond Superman's abilities, and has even rendered Superman a normal mortal being.