‘A king had a beautiful daughter,’ begins David Foster’s new book: 204 pages between grey boards, a reproduction of Filippo Lippi’s Madonna con Bambino e due angeli on the covers, the author’s name itself visible only on the acknowledgements page, in rather small writing.

A king had a beautiful daughter. She was so beautiful that any man who saw her at once wanted to marry her. Well, the poor old king got so fed up with this he locked his daughter in a round tower where an old monastery had once stood. Round towers have a door about four metres off the ground and this one was no different. If you want to know what a round tower looks like, there are sixty-five left, in part or in ruins, through Ireland, a few in Scotland, one on the Isle of Man

Now, the king has lost the key to that tower, and has proclaimed that any man who can get the door open can have his daughter’s hand, and lo!, one day a poor woodcutter decides that he will give it a go.