“Physics class taught me that if I jumped into a tube that extended all the way through the earth, I’d fall endlessly from pole to pole, borne back and forth by gravity. Leah Hager Cohen made me feel the same sensation with To & Fro, a twin-tale novel . . . full of intelligence, humor, and deep feeling. It’s as if Eloise and Alice walked hand-in-hand through the looking glass and I was able to follow them.”