Tell Me Your Favorite Book About Walking

There are so many good books, essays, poems, and, hell, even songs about walking. I’m preparing tonight to go on a long walk with an author who wrote an entire book about hiking and trails (and a whole slew of other things), which you’ll be able to read about in the coming weeks. But as I pack my bags and double check my gear, I’m wondering: what are some of your favorite books about walking?