P.S. Just the other day, I ordered a new book from Thriftbooks ( for reasons) and it arrived in that cut to size thin but stiff sticky on one side cardboard, when two pieces are slapped together around the book. That seems to work rather well, and the title, a paperback, arrived in perfect shape.

It shipped from a Texas location, and I seem to recall one or two other books from them that were also shipped that way. And that at least one of those also came from a Texas location of theirs.