Great book!
David Brainerd's diary is flat amazing, and for me is a wakeup call in a sea of casual Christianity. The suffering, joy and humility of this man shine through his writings which he never meant for publication (THANK YOU Jonathan Edwards for seeing the incredible value in them! The short bio of Edwards was very good as well) show a very great saint of God, through his continual struggles, feelings of inadequacy and longing for God. There is no talking down here--he would categorize himself as the chief of sinners.
This version of his writings is easy to read as far as print size etc, but not a quick or a casual read. I use it like a devotional. In fact, these days, after the Word of God, his journal is my go-to book for spiritual adjustment.