I just purchased the 2023 edition of "The Early Paper Money of America", and also wanted to get the 1967 1st edition by Eric P. Newman, who died in 2017. They both showed up in the mail today.
The 1st edition copy I got was in great condition, but had an old clipping from a newspaper stuck on the title page. It had been there a long time, as there was a stain on the blank facing page. I didn't pay much attention to it, but carefully worked it loose (there was just one tiny bit of sticky substance holding it in place). After removing it, I saw it was the Democratic ticket for the 1900 election!
On the reverse side I see that the newspaper was from Seattle, as there are two prominent ads for the Third Avenue Theatre, "Seattle's Uptown Theatre". I Googled it, and saw that the theatre was torn down in 1906 or 1907 when major reconstruction was being done in that area.
Before I looked at it, I assumed it was being used as a bookmark, but with it being that old it must have been a keepsake kept in the book that was forgotten about. And, yes, I did flip through the rest of the book to see if there were any other interesting things tucked in between the pages! No luck, though...

