Cappadocia’s “fairy chimneys” were produced as wind and rain eroded away the soft volcanic tufa, leaving layers of harder nonvolcanic rock perched precariously on top. According to Robert Ousterhout (“The Cave-Dwellers”), this region of central Turkey—occupied in antiquity by Romans, Persians and Arabs—reached its floruit in the 10th and 11th centuries, when Byzantine settlers cut intricate dwellings into the soft rock. Who were these settlers? Veronica Kalas (“Monasteries? Heavens, No”) says they weren’t monks, as scholars have long supposed.