M: it was stamped in scarlet on his cardinal-coloured pullover. It was written in black on his birth certificate - and again, now, you have to think, scribbled on some anonymous slip of a form recording his unlamented death. And it was there, of course, all over the news, in the chat rooms, on the blogs and social networking sites that heralded his feats - or disparaged him. M: it was on everyone's lips. You couldn't miss him that spring and summer when his star, loaded with such dazzling gravity, lifted our hearts. Everyone knew him. Or really, everyone knew of him. But nobody knew him better than me. And his name was . . . Part mystery, part coming of age, part audacious grasp for celebrity and its riches, Now You Know shows Charlie in an imagined dialogue with Stephen Fry, recounting the summer when he was seventeen, and lived next door to a man who he's certain was the mysterious hero, known only as M.