If M-Theory and Superstring is simplified any further, we can all skip undergraduate physics and spend our graduate school years unravelling M-Theory. Greene has done a marvellous job.<br>I am a Family Physician and  an author (titles in Metaphysics); I devoured The Elegant Universe in a  week or less. Greene's ability to bring lofty astrophysical concepts to the  masses in the trenches is only reminiscent of the hugely successful efforts  of the late Carl Sagan.<br>M-Theory is up to something. I wouldn't be  surprised when, in a few years, "M" can explain that the universe  is neither expanding forever, nor destined to shrink again; but that this  dimension ("our" universe) is currently only undergoing a  "pinch," an inflation, or is in the process of reparing one--a la  Super String.<br>Greene is honest--never hiding an "all this could be  wrong" admission. But so what if it's all wrong? Newton invented  Calculus to explain the world of his concept--and it worked some. If we  "invent" "M" and it works, we will be that much further  ahead. If it doesn't, we move on.<br>Thanks to Greene, we the (lay)people  can be part of this exciting and challenging paradigm. The  "Elegant" in the book's title applies equally well to Greene's  literary effort and style.<br>Great job!