- Script:
- Gardner Fox
- Pencils:
- Carmine Infantino
- Inks:
- Joe Giella
- Colors:
- ?
- Letters:
- ?
- Genre:
- science fiction
- Characters:
- Commander John Yardley
- Synopsis:
- In a future where Earth is ravaged by the after-effects of an atomic war, scientists decide to change the past so the atom bomb was never created.
- Reprints: show reprint note before migration
Credits for script, pencils and inks confirmed from Julius Schwartz's editorial records, provided by DC Comics (April 2007).
- Script:
- ?
- Pencils:
- ?
- Inks:
- ?
- Colors:
- ?
- Letters:
- ?
- Synopsis:
- House ad for Challengers of the Unknown #1.
Shows a differently colored cover than the actual printed issue. Sequence added per Ken Rowand, December 2008.
- Script:
- ?
- Pencils:
- ?
- Inks:
- ?
- Colors:
- ?
- Letters:
- ?
- Genre:
- Fact
Information for this sequence from Arthur Lortie, September 2008. Sequence order corrected per Ken Rowand, December 2008.
- Script:
- Gardner Fox
- Pencils:
- Sid Greene
- Inks:
- John Giunta
- Colors:
- ?
- Letters:
- ?
- Genre:
- science fiction
Page count added per Ken Rowand, December 2008.
- Script:
- Otto Binder
- Pencils:
- Gil Kane
- Inks:
- Bernard Sachs
- Colors:
- ?
- Letters:
- ?
- Genre:
- science fiction
Page count added per Ken Rowand, December 2008.
- Script:
- Gardner Fox
- Pencils:
- Sid Greene
- Inks:
- Bernard Sachs
- Colors:
- ?
- Letters:
- ?
- Genre:
- science fiction
Page count added per Ken Rowand, December 2008.