You can fix this issue in minutes. Just hold the book closed and press along the page edges with your thumb and forefinger, applying moderate to high pressure, pushing the pages back into the spine. After a minute of applied pressure, you will be surprised to see the spine block has reset back into its original position. The longer you hold prolonged pressure, the better the spine sinks back into place. Also considering gravity is to blame, just leave the book on its spine for a long time. Let gravity push the pages back into their original position.

Ingenious, simple solution. I didn’t realize this was even a thing.

Mike, I forgot to mention this earlier. It was something I found out quite by accident. I have a copy of "The C Programming Language 2E" (Ritchie; Kernighan) in hardback. It is in excellent condition, but at the time, it had a twist in it. That is, one cover was lower than the other. I put it in a tight-fitting box around its perimeter, along with some other books that just happened to be the same size, so the box was packed tight. When I came back to them months later, the twist in the book had gone. It was back to normal. No one was as surprised as I was.

Another interesting video, thank you.

A proper rounded spine with enough swell would be able to prevent this from happening. The signatures would work like bricks in an arch, preventing the sag. Unfortunately, even expensive hardbacks these days are made to a budget.

Brilliant. Fantastic video. Just checked my no.1 book (Allen Lane hardback 2020), and there it is... a very slight gap. Base cardboard now in place. Completely good. Many thanks. When am I next Bedford way!?

Great video, and sadly a lot of my expensive books have this problem. I did some research and a suggestion i was given was to get acid free foam from art stores. The acid free is important because it wont colour your pages as other material you can use. I hope this trick stops the problem, and maybe even fixes it. Thanks for the video

Mike, that is brilliant! As I was watching I wondered if you had something like a plinth in mind and there it was. Occasionally after purchasing a second hand book I find a previous owner has written a note in the front, perhaps when given it as present. Have you ever found anything interesting written in the front of a book? Rob and Claire

You could collect paperbacks instead of hardbacks, but ........ hmmm ....

Q: How much time does it take for a book to have this noticeable 'drop' ? Does it take around ~1 year, or more like ~10 years?