"The Mystery of Spaceman X!" #20
| Series | Justice League Of America |
| Number | Vol. 1 #20 |
| Publisher | DC Comics, National Periodical Publications, Inc. |
| Date | 1963-06 |
| Type | Comic Book, Softcover |
| Language | English |
| Cover Artist | Murphy Anderson, Mike Sekowsky |
| Editor | Julius Schwartz |
| Inker | Bernard Sachs |
| Letterer | Gaspar Saladino |
| Penciler | Mike Sekowsky |
| Writer | Gardner Fox |
| Genre | Superhero |
| Published in | Sparta, Illinois |
| Pages | 32 |
| Characters | Wonder Woman (Earth 1), Superman (Kal-El)(Earth 1), Batman (Bruce Wayne)(Earth 1), Green Arrow (Oliver Queen)(Earth 1), Aquaman, Flash (Barry Allen), Atom (Ray Palmer), Green Lantern (Hal Jordan), Martian Manhunter (J'onn J'onzz), Supporting Characters:, Snapper Carr |
| Story Location | Planet Allamar; Allamar City, Rhode Island; Secret Sanctuary |
| Links | https://dc.fandom.com/wiki/Justice_League_of_America_Vol_1_20 |
Added by mlopinto