| Issue | #4 |
| Published | April 1966 |
| Cover Price | 0.25 USD |
| Pages | 68 |
| Editing | Sam Schwartz |
| Genre | Superhero |
| Pencils | Reed Crandall |
| Inks | Wally Wood |
| Characters | Dr. Sparta (first appearance) |
| Genre | Superhero |
| Script | Len Brown |
| Pencils | Dan Adkins; Wally Wood |
| Inks | Wally Wood |
| Script | Steve Skeates |
| Pencils | Mike Sekowsky |
| Inks | Frank Giacoia |
| Notes | vs. Mastermind 1st |
| Reprinted | in NoMan, the Invisible T.H.U.N.D.E.R. Agent (Tower, 1967 series) #42-672 |
| Pencils | Wally Wood |
| Inks | Wally Wood |
| Reprinted | in T.H.U.N.D.E.R. Agents (Tower, 1965 series) #15; in T.H.U.N.D.E.R. Agents (Tower, 1965 series) #18; in NoMan, the Invisible T.H.U.N.D.E.R. Agent (Tower, 1967 series) #42-672; in Hall of Fame Featuring the THUNDER Agents (JC Comics, 1983 series) #3 |
| Characters | THUNDER (origin) |
| Synopsis | The origin of THUNDER. |
| Genre | Superhero |
| Pencils | Wally Wood |
| Inks | Wally Wood |
| Script | Steve Skeates |
| Pencils | Mike Sekowsky |
| Inks | Frank Giacoia |
| Notes | origin and 1st appearance of Lightning. vs. Baron von Kampf 1st |
| Reprinted | in T.H.U.N.D.E.R. Agents (Tower, 1965 series) #20 |
| Pencils | Reed Crandall |
| Inks | Wally Wood |
| Notes | with NoMan and THUNDER Squad |
| Reprinted | in T.H.U.N.D.E.R. Agents (Tower, 1965 series) #20 |
| Pencils | John Giunta |
| Inks | Dan Adkins |
| Reprinted | in Menthor (Tower, 1967 series) #42-674 |