"The result of these walks on my head is tangible: they refined what I can see. My mind can prepare my eyes to spontaneously find a leaf gall, to hear an air conditioner's hum, to smell the sickly sweet smell of garbage on a city street (or the fragrance of my own soap on my face, instead). It can tune to the sounds of my own breath, the feel of my heartbeat, or the shifts of my weight as I walk and negotiate sidewalk space. I can feel my hip bones rotating in their sockets as I walk, my arms swinging in rhythm with my legs. I can hear the conversation behind me, in front of me, in a passing car — or just the jingle of my dog's tags as he strides alongside me down the street. For me, walking has become less physical transit than mental transportation. It is engaging. I have become, I fear, a difficult walking companion, liable to slow down and point at things. I can turn this off, but I love to have it on: a sense of wonder that I, and we all, have a predisposition to but have forgotten to enjoy.

"There could be an exhaustion in being told to look, to pay attention, to be here now: one might feel put upon, as though being chastised for being neglectful. Nearly all the people I walked with — some of whom were, in essence, professional attenders or lookers — reproached themselves for not paying good enough attention.

"Do not sag with exhaustion. There is no mandate; only opportunity. Our culture fosters inattention; we are all creatures of that culture. But by making your way through this book — by merely picking it up, perhaps — you, reader, are in a new culture, one that values looking. The unbelievable strata of trifling, tremendous things to observe are there for the observing. Look!"