Appearing in "We Must Destroy...the Cobalt Man!"
- Coffee A Go-Go patrons
- Never-Say Diner customers
- Iron Man - (Cameo) 
- Juggernaut - (Cameo)
- Mimic (Mentioned)
- Avengers (Mentioned)
- Metro College Stadium
- Monkee's Paw
- Greenwich Village
- Roberts Research, Inc (First appearance)
- Ralph Roberts' truck
- Warren Worthington III's Mustang
Synopsis for "We Must Destroy...the Cobalt Man!"
- Synopsis not yet written.
- Ted Roberts begins to suspect that Jean Grey and Scott Summers are really Marvel Girl and Cyclops respectively.
- Candy Southern's name is misspelled as Sothern in this issue.
- This issue is reprinted in many other comics and books, see references for more info.
- Let's Hear It For Merry Marvel's Own Peerless Periodic Table!
- Good-as-Gold Editing by: Stan Lee
- Solid-Silver Scripting by: Roy Thomas
- Platinum-Plated Pencilling by: Werner Roth
- Iridium-Bright Inking by: John Tartaglione
- Lead-Lined Lettering by: Sam Rosen
- Stable Elements All!
- references: X-Men #29 and Tales of Suspense #89
- Those credited are applauded with the approbation "Stable elements all". (As opposed to the cobalt in the cobalt man suit, for instance, which is radioactive).
- In Page 4, Panel 1, Professor X asks Scott to give Jean back the books the X-Men used when Kukulcan was posessing El Tigre.
- Ralph mentions that he's making a ship that can travel to the Earth's Core. The X-Men will use this ship later in X-Men #34
- Write your own review of this comic!
- Discuss X-Men Vol 1 31 on the forums
- Images from X-Men Vol 1 31
- While Iron Man appears in one panel, he doesn't actually appear in the *story*, the panel is just there to explain that Iron Man is currently busy elsewhere and thus not around to defend his factory.
- Reprinted in the following comics/TPB's: