According to Holland Cutter, "For Michelangelo drawing was the most practical and personal medium; it was a laboratory, a diary, an end in itself. If you could do a perfect drawing, he came to think, why bother to turn it into a painting or sculpture? Perfection in any form was the goal."
The show up at the Morgan Library and Museum in midtown Manhattan, examines the role of drawing in 16th Century Florence. It triggers thoughts of the current role of drawing; what an intimate gesture, unaffected by artifice it is. How immediate and wholly satisfying it can be, and how the disparity between the formal works an artist presents, and casual drawings and studies can be quite startling.
Closer to home, the best example of this I can think of is the Lucian Freud etching currently on view at MOCA. Freud's paintings are celebrated as violent, deliberately ugly and ungainly portraits of the human body on par with those of Titian, Rubens and Velázquez, but the etching on view (in this case taken as an example of the artist's drawn work) lacks the power of Freud's paintings, and instead exists for the viewer as an example of process.
Perhaps that is the crux of the drawn line, it is a look behind the curtain into something honest and unadorned; relying on a quality of of line and an arrangement of form in (or against) space.