the tag hangs in the slot the book used to occupy. it is a polite gesture and also, in this household, an obligation — a small clerkship. for a fortnight the shelf will read: green book, borrowed, by D. afterwards the shelf will read, again: green book.
the green book did, in the event, come back. it came back four months later, slightly thicker — read closely, marked once or twice in a careful pencil, dampened by an autumn morning and dried unevenly on a radiator. the tag was taken down. the owner did not, on opening the cover, mind the pencil; the borrower had been right about the kind of book it was.