Some people make notes in the margins of the books they're reading.
Sometimes, of course, marginalia grow into complete articles on their own and on rare occasions, they even become more important than anything contained in the book whose pages they embellish. No one has either found the proof that Fermat said he'd found, nor found proof that he'd really found it either. The margin of the human body is its skin. Its colour can make the difference between life and death in some parts of the world. My reason for giving my column this title is by no means so ambitious.