Sometimes there is a large quantity of stock ordered of one particular title and some less-borrowed copies end up in “discard” (as it’s known in the trade), with eventually one copy remaining in the system in case of a sudden upswing in interest.

Every so often, the shelves for one genre get completely full, in which case less-popular copies are likely to be removed and sold. That said, in such a case the library will try to get one of its fellow libraries to take the book off its hands first.

Occasionally, a book is put in the discard pile by mistake and subsequently sold off.

And there’s the more typical reasons – that a book is damaged, out of date or simply been subject to a one-year-old checking to see if paper/cardboard/plastic can be eaten.

The amount that goes on buying new books is minimal – it would be more likely that the sale of a book covers the cost of a new book’s jacket (which is very useful for the items which are popular!)

Next week: a novel use for bookies’ pens.