I’ve been thinking about physical books lately: the size of what we read versus the size of smartphones; how the US military passed out more than 120 million paperbacks to soldiers during World War II; the history of mass market paperbacks (which aren’t much bigger than smartphones) and who buys hardcovers; and the so-called crisis of reading that I’m both aware of and insulated from here at the Review . I decided to do some extremely unscientific research and count the number of people reading books on the subway. I made a diagram of each car I rode in, making a mark on the seats where a person was reading a physical book. I saw the greatest number of books per car on the G train, which connects Brooklyn to Queens. Most passengers were reading paperbacks, though I did have the odd hardcover sighting. I saw Salinger and Dostoevsky and Suzanne Collins.…