My guest on this week's Book Club podcast is Ashley Ward, author of Sensational: A New Story of our Senses, which takes us on a cultural, historical and neurobiological tour of the sensorium. Along the way he tells me why Aristotle's notion of five senses is a convenient but cockeyed idea, why men are best letting their wives pick out the curtains, why we call ginger-haired people "redheads" and, oddly, how a pooping dog might do in a pinch as an aid to navigation.