Topps has it as a 1966 issue, which is possible but the show was syndicated in 1965 and a generation of late boomers grew up watching the Man O' Steel after school each day. No matter, it's from 1965-66 either way but the big news was confirmation the white back version, which is one of the tougher Topps issues, has 44 subjects. The two orange backed varieties, which are common, both go to 66 but the last 22 cards make up a puzzle while the first 44 have text. So the 44 card count for the white backs makes a lot of sense. I'm not sure every one of those numbers has been confirmed but that number seems good.
The fronts are all similar, except the clarity on the white backs is better. I've shown a lot of this before but it's worth revisiting:
The white backs are subject to toning unfortunately. There are two types of orange backs, like so, three (or four!) if you count the puzzle:
You will note the WATCH SUPERMAN ON T.V. tag line; we'll get back to that momentarily. Here is one of the two puzzle backs but there's a catch-there are two types because one is a photo and one is a drawing. This one is from the latter puzzle.
You can see both puzzle backs at the Net54 Gallery, totally worth the click.
There are also two wrappers, one with gum and one without, plus some other differences:
So obviously the orange backs that have the TV tagline came in the packs with the same wording on the wrapper. And if you look closely, the "TV" packs did not come with gum. This makes me think the cards without the TV tagline were sold first by Topps, since they were in the gum business after all, then they either worked out some kind of deal or got dragged into a fight between the comics publisher (National Periodical Publications) and the TV production company.
It's all a bit strange but it might explain why there are two types of puzzle as well. I have to check and see if the puzzle pieces are harder to find. If there are no white back puzzle pieces, then maybe it was a 44 card set to start out with. Great Caesar's Ghost! This is way more complicated than it has any right to be.