Do People Still Collect Booklet Panes?

I see my mistake, the ones Rider referred to were self-adhesive ones sold by vending machines where there was no cardboard cover, they used the back of the liner as the booklet cover.

However, the makeshift booklets while produced by MDI, were not issued by MDI. They were issued by USPS.

As for how many varieties of MDI booklets exist, it depends on what you call a variety. If you count only booklet cover variations, then the number known can easily be added up.

I stand corrected. My use of the word "issued" was not precise. Obviously, only the USPS is authorized to issue US stamps.




Because a MDI booklet may contain a partial pane of a previously issued pane of stamps, the exact position of the pane used could vary from booklet to booklet for the same number of stamps. All collectors of MDI booklets I've encountered consider two MDI booklets that contain different pane positions as two varieties. I think this is the root of the difficulty in determining how many varieties of MDI booklets that have been produced.

By that definition there are far more than the 50 you have managed to acquire.

That is exactly why I said in my earlier post that I was still missing some varieties.