| Issue | #51 |
| Published | December 1968 |
| Cover Price | 0.12 USD |
| Pages | 36 |
| Editing | Stan Lee |
| Characters | The X-Men [Angel; Beast; Cyclops; Iceman; Marvel Girl]; Erik the Red |
| Genre | superhero |
| Pencils | Jim Steranko |
| Inks | Jim Steranko |
| Characters | The X-Men [Angel; Beast; Cyclops; Iceman; Marvel Girl]; Lorna Dane; Mesmero (Villain); Demi-Men (Villain); Magneto Robot (Villain); Erik the Red (Villain) |
| Genre | superhero |
| Script | Arnold Drake |
| Pencils | Jim Steranko |
| Inks | John Tartaglione |
| Letters | Sam Rosen |
| Reprinted | in Marvel Special (Marvel Italia, 1994 series) #16 |
| Characters | Beast (origin continued); Hank McCoy (as teenager); Professor X; X-Men [Cyclops; Iceman; Angel]; Norton McCoy; Edna McCoy; El Conquistador (Villain); Chico |
| Genre | Superhero |
| Script | Arnold Drake |
| Pencils | Werner Roth |
| Inks | John Tartaglione |
| Letters | Herb Cooper |
| Notes | The Origins of the Uncanny X-Men! part 14, origin of the Beast part 3, pages 1 and 2 of this story is not reprinted in the Amazing Adventures #17 and X-Men: Mutations #nn reprints. |
| Reprinted | in Marvel Masterworks: The X-Men (Marvel, 2003 series) #5; in Essential Classic X-Men (Marvel, 2006 series) #2 [black & white]; in Amazing Adventures (Marvel, 1970 series) #17 (March 1973) [pages 3-5]; in X-Men: Mutations (Marvel, 1996 series) #nn (1996) [pages 3-5]; in Marvel Special (Marvel Italia, 1994 series) #12 (Novembre 1997) [abridged] |