in Thoreau’s Journal: 

Books are to be attended to as new sounds merely. Most would be put to a sore trial if the reader should assume the attitude of a listener. They are but a new note in the forest. To our lonely, sober thought the earth is a wild unexplored. Wildness as of the jay and muskrat reigns over the great part of nature. The oven-bird and plover are heard in the horizon. Here is a new book of heroes, come to me like the note of the chewink from over the fen, only over a deeper and wider fen. The pines are unrelenting sifters of thought; nothing petty leaks through them. Let me put my ear close, and hear the sough of this book, that I may know if any inspiration yet haunts it.

There is always a later edition of every book than the printer wots of, no matter how recently it was published. All nature is a new impression every instant.