When Gregor Samsa woke up one morning he was a gigantic insect; when Professor Donald N. McCloskey woke up one morning he was a gigantic woman. It is a matter of opinion as to which metamorphosis was the more bizarre or surreal.

Of course, Professor McCloskey’s metamorphosis took rather longer than Mr. Samsa’s, and was much more expensive. In fact, he had been a cross-dresser for many years when he had what he calls his epiphany, a quasi-supernatural message (from where, from whom?) telling him to drop mere pretence and actually be a woman, anatomy and all. It was his hope and ambition that henceforth all his acquaintances would be able to say to him, “Seems, madam! Nay, it is; I know not ‘seems.’”

In the old days, people had religious conversions; nowadays, they have sex changes. Crossing[1] is a memoir of the emergence of the imago...