| Issue | #21 |
| Published | September 1988 |
| Cover Price | 0.75 USD; 1.00 CAD |
| Pages | 36 |
| Editing | Mike Carlin; Renee Witterstaetter (assistant) |
| Notes | Corrected cover pencil & ink credits from Ralf H. Kienzle (December 15, 2005). |
| Characters | Superman [Clark Kent; Kal-El]; Supergirl [Matrix] |
| Genre | Superhero |
| Script | John Byrne |
| Pencils | John Byrne (signed) |
| Inks | John Byrne (signed) |
| Notes | Corrected cover pencil & ink credits from Ralf H. Kienzle (December 15, 2005). |
| Characters | Superman [Clark Kent; Kal-El]; Supergirl [Matrix] (Pocket Universe); Lex Luthor (first appearance; Pocket Universe); Pete Ross (Pocket Universe); Lois Lane; Perry White; Jimmy Olsen; Jonathan Kent; Martha Kent; Lana Lang; VILLAIN: Lex Luthor |
| Synopsis | Supergirl introduces herself to Superman, and then they are transported to the Pocket Universe. |
| Genre | Superhero |
| Script | John Byrne |
| Pencils | John Byrne |
| Inks | John Beatty |
| Colors | Petra Scotese |
| Letters | John Costanza |
| Notes | Story continues in ADVENTURES OF SUPERMAN (DC, 1987 series) #444. |
| Script | Renee Witterstaetter |
| Pencils | Jerry Ordway |
| Inks | Jerry Ordway |
| Letters | typeset |
| Notes | Letters from readers - David Metz, Neil Ahlquist, Stacy Brian Barley, Sam Hatcher, Mark Glinskie, Ed Moretti, R.K., Paul Anthony Lhossas, Bob Clinton, Carlos Pico, Jr., Tim Moyle and Howard T. Kodd - and responses from Renee Witterstaetter. Preview of cover to ADVENTURES OF SUPERMAN (DC, 1987 series) #444. |