Like you, I also have long out of print books, that would be impossible to replace and IF I lost, would break my heart.
My precious Watkins The Old Straight Track even survived.
It’s a little rougher than it was before but still have it.
We had some great used bookstores locally and I’d go drag home heavy books on megalithic cultures, standing stones and dozens of variations of what people once thought them to be.
Just the photos alone in them are precious to me.