For a good 4 years my son was obsessed with all things transportation. I mean this went beyond the usual pre-school Thomas and Friends to a love of all things movement. At age 4 he knew three-letter abbreviations for many airports. He was like a pint-sized Google maps—with a starting point and destination, he could tell you the fastest subway routes to get around. Even after living in the suburbs for quite some time, this is still his favorite book.