The twelfth and thirteenth centuries witnessed an explosion of Christian interest in the meaning and workings of the natural world a "discovery of nature" that profoundly reshaped the intellectual currents and spiritual contours of European society yet to all appearances, the Jews of medieval northern Europe (Ashkenaz) were oblivious to the shifts reshaping their surrounding culture. Scholars have long assumed that rather than exploring or contemplating the natural world, the Jews of medieval Ashkenaz were preoccupied solely with the supernatural and otherworldly: magic and mysticism,...