Cultural history is littered with accounts of transformative reading experiences. From Abraham Lincoln’s supposed assertion that Uncle Tom’s Cabin e ectively started the Civil War to the recent bestseller Th e Book Th at Changed My Life, claims for reading’s power abound. is volume is born out of a desire to understand those claims more fully. To say that reading is transformative, that reading can change the direction of a culture or a life, is to assert that reading has power – but how can we gauge that power, or measure reading’s impact? e question is di cult enough to answer for ourselves, about the books we have read most recently, and it becomes thornier still when we ask it about readers in other places and, particularly, in earlier times.