From Chapter 2.
'I went to the woods, because I wished to live deliberately. To front only the essential facts of life and see if I could not learn what it had to teach and not when I came to die discover that I had not lived. I did not wish to live what was not life. Living is so dear, nor did I wish to practice resignation, unless it was quite necessary.
I wanted to live deep and suck out all the marrow of life. To live so sturdily and sparten-like as to put to route all that was not life. To cut a broad swath and shave close, to drive life into a corner and reduce it to its lowest terms and, if it proved to be mean, why then to get the whole and genuine meaness of it, and publish it's meaness to the world. Or, if it were sublime to know it by experience, and be able to give a true account of it in my next excursion. For most men it appears to me are in a strange uncertainty about it.'
Listen to this free Librivox audio book chapter 2, part 2 here (12MB Download)