DC · June, 1965
1st Appearance of Blak-Du (Phantom Zone criminal); Versus Phantom Zone criminals; Jor-El travels back in time and visits Earth as a teen-ager; Superboy loses his super-powers; Superboy refers to Jax-Ur, Kru-El, and Professor Vakox as the first three criminal scientists exiled to the Phantom Zone; Time travel
Clark Kent’s Single Identity!; The Stolen Super-Identity; Jor-El’s Visit to Earth!
Writer: Otto Binder
Artists: George Papp, Curt Swan