The title refers to the Glasgow City Crest which represents the legend which is told of Saint Mungo who is the Patron Saint of the City.
The book was well written and apparently had many references to previous books in the series but this doesn't spoil the enjoyment as I've only read one other of her books. It is a little pedestrian and the characters seem a little 'dry' and predictable but it was ok. I was very keen to finish it before the end of the Games just on point of principle.
My other physical July book was the fab James Oswald Dead Man's Bones but I am going to give that a post of its own.