| Issue | #21 |
| Published | April 1945 |
| Cover Price | 0.10 USD |
| Pages | 52 |
| Editing | Charles Biro; Bob Wood |
| Pencils | Charles Biro |
| Inks | Charles Biro |
| Script | Charles Biro |
| Pencils | Radcliffe |
| Inks | Radcliffe |
| Synopsis | Swoop consults on phone with Dickie Dean |
| Pencils | Bob Montana? |
| Inks | Bob Montana? |
| Script | Bob Wood? |
| Pencils | Rudy Palais |
| Inks | Rudy Palais |
| Script | Dick Wood |
| Letters | typeset |
| Script | Dick Wood |
| Pencils | R. W. Hall |
| Inks | R. W. Hall |
| Characters | Leonardo Da Vinci |
| Script | Dick Briefer |
| Pencils | Dick Briefer |
| Inks | Dick Briefer |
| Script | Bob Wood? |
| Pencils | Alan Mandel |
| Inks | Alan Mandel |