In the column list the column labelled
Date has the lookup name
timestamp
But in the book list it shows a lookup name of
date
I've never understood why.
FWIW, I don't need to know when I added a book to a library, so soon after I started using calibre I re-purposed the Date column. When I add a book I clear it with '-', and when I finish reading the book I set it today with '='. This hasn't caused me any grief. I don't connect devices to calibre.
BR