An okay golden age mystery set at the time of the San Francisco Golden Gate Exhibition of 1939. The lead characters are pleasant and don't act too outrageously, even though they seem to court danger without much thought. The fair itself doesn't play a big part in the story, except for some venerable olive trees (the background of which I found more interesting than some of the plot.) In the end it was all a little more complicated than it should have been, but not a total waste of time.