Looking through a book of drawings by Holbein I realize several moments of truth. A nose (a line) so nose-like. So line-like. And then I think to myself "so what?" It's not going to solve any of my problems. And then I realize that at the very moment of appreciation I have no problems. Then I decide that this is a pretty profound thought. And that I ought to write it down. This is what I have just done. But it doesn't sound so profound any more. That's art for you. (Joe Brainard)
...by means of line, Holbein captured quite precisely, with simplicity, elegance, and great lightness of touch, the individuality of his subjects -- without resort to flattery, drama or idealization.
Just those remarkable lines, always varying in weight but always strong and sure and extraordinarily revealing.... Holbein seems to employ line to see into the soul of a subject. (Tom Clark, in comments)