| Issue | #1 |
| Published | April 1940 |
| Cover Price | 0.10 USD |
| Pages | 68 |
| Editing | Ned Pines |
| Characters | Major Mars |
| Pencils | L. North |
| Inks | L. North |
| Characters | The Mask [Tony Colby] (first appearance; origin); Silk Davis (first appearance); Carol Smith (first appearance); Olly Snate (first appearance; villain) |
| Script | Raymond Thayer? |
| Pencils | Raymond Thayer |
| Inks | Raymond Thayer |
| Colors | Raymond Thayer? |
| Characters | Major Mars (first appearance); Grag (first appearance; a robot); Joan Jilson (first appearance); The Space Emperor ([Kells] (first appearance; villain) |
| Pencils | Max Plaisted |
| Inks | Max Plaisted |
| Notes | only appearance |
| Characters | Sgt. Bill King (first appearance); Nazis (villains) |
| Pencils | Leonard Sansone |
| Inks | Leonard Sansone |
| Characters | Jim Hatfield (first appearance; a Texas Ranger); Capt. McDowell (first appearance); Padre Borasho (first appearance; villain; death); Sen. Crocker (first appearance; villain); Slade (first appearance; villain) |
| Characters | Gunner Thompson (first appearance; only appearance) |
| Characters | Hy Hardy (first appearance; only appearance) |
| Pencils | Ken Browne |
| Inks | Ken Browne |
| Script | Sam Brant |
| Letters | typeset |
| Characters | Dan Williams (first appearance); Caroline Forbes (first appearance); John Blodgett (first appearance; villain) |
| Pencils | Ray Lowry |
| Inks | Ray Lowry |
| Characters | Make-Believe Mickey (first appearance) |
| Script | Klaus Nordling |
| Pencils | Klaus Nordling |
| Inks | Klaus Nordling |
| Colors | Klaus Nordling |