This was originally scheduled for Showcase (DC, 1977 series) #104-106 to coincide with the premiere of Superman: The Movie, but was rescheduled for issues #110-112 when the film's release date was delayed. Revised and released as the first ever limited series.
Indicia titles:
#1 and #2: THE WORLD OF KRYPTON
#3: WORLD OF KRYPTON