Ratzinger’s Faith: The Theology of Pope Benedict XVI, by Tracey Rowland; Oxford University Press, 2008, $39.95. When my wife and I married eleven years ago, the priest who celebrated our nuptial mass caused scandal by requesting (it being a Mass celebrated according to the 1962 Missal) that communicants knelt and received the host on the tongue. Benedict XVI’s insistence on the same at the recent World Youth Day Mass is, therefore, a subtle but significant shift. For Tracey Rowland in her book Ratzinger’s Faith such a return to past practice is not a retro indulgence but goes to the heart…