X-Ray Vision

[MBE]

When did Superman first have X-Ray or Telescopic vision? Meaning which story was the first to mention it?

[Super Monkey]

When did Superman first have X-Ray or Telescopic vision? Meaning which story was the first to mention it?

Don't know for sure, but this will give you some clues:
https://www.supermanthroughtheages.com/wiki/index.php/Superman#X-Ray_Vision_and_the_Other_Optical_Powers

[MBE]

I actually read this and think it is a very good article. I posted my question here ibecause it is the only power it is vauge on.

[Uncle Mxy]

It was fairly early on.  Accidentally looking at the eyechart in the next room was the excuse for him to not go into WWII.  The Fleischer/Famous-era cartoons had X-Ray Vision in one or two of them, and the beginning credits reflected that.

[MBE]

I think by 1940 it was there I just had trouble finding which was the first use of it.

[crispy snax]

i just brought superman chronicles 2 (all superman stories in chornlogical order! it claims) and in action comics 18 superman first uses his x ray vision and (super sensitive hearing) to listen in on some crooks, so thats pretty early on (november 1939). it comes across as a plot device really, superman spontaneiously uses a power he has never been shown to have before, just to fill in a few frames... still it was the 30s so whos complaining?