Zen in the Art of Archery, by Eugene Herrigel. This is the book that Cartier-Bresson would recommend to photographers. Photography today is largely discussed in cerebral terms; people tend to forget that it is also a kind of athletic activity – one that mixes shot-making with intuition. If Zen is not your thing, a distant runner-up could be The Inner Game of Tennis, by Timothy Gallwey. If you are feeling lazy, you could just watch any of the early Star Wars movies where Luke Skywalker turns off his technology and uses the Force instead – finally this is the only way for him to hit the target.
Vincent Van Gogh’s Letters to Theo. The world was Van Gogh’s studio; when he painted the night café he was actually there. My photojournalism teacher in high school, Mr. Van Zante, told me to remember that the main thing was just to be there - to somehow place yourself physically before your subject – so move those legs.
My Life and My Films, by Jean Renoir. These are highly readable words from the master of lyrical realism and one of my favorite filmmakers. As an aside, how wonderful it would have been if the exquisitely literate Walker Evans had also written an autobiography.
Any great literature – there’s so much. Evans was fond of Flaubert but there’s a vast wealth of words from Aristophanes on. See how high the bar for excellence can be set.
Anything that can connect you to the distant past. The Nature of Paleolithic Art (R. Dale Guthrie), for instance, or Unearthing Atlantis (Charles Pelligrino), which is about the excavations of an advanced civilization that existed before the Greeks on the island of Santorini (which is where I am heading as I type this out on a plane). Try to bring something to your work that is not just from your generation.
For extra credit – the Sufi poets Rumi (Coleman Barks, translator) or Hafiz (Daniel Ladinsky, translator).