Earlier this spring,  Lauren Kane journeyed up to the Cloisters —the Metropolitan Museum of Art’s outpost on the northern tip of Manhattan, which houses European art inside a complex of buildings cobbled together from the ruins of several medieval cloisters brought over from France and Catalonia in the early twentieth century—to visit “Spectrum of Desire: Love, Sex, and Gender in the Middle Ages.” As Kane writes in the  NYR Online , the exhibition was rife with “transgressive delight”: “saddles rowdy with double entendre, demure coin purses,” “a painting of the Madonna nestled within a yonic wound-shaped frame,” “a large plate embossed with a scene of a wife paddling her husband’s ass,” “a copper aquamanile…in the shape of a woman riding a man,” and many more objets d’art, both secular and devotional, that would raise eyebrows even today, never mind six hundred years ago.…