Preface<br >IN THE MOVIE Star Wars， Luke Skywalker s<br >adventure begins when a beam of light shoots<br >out of the robot R2-D2 and projects a miniature<br >three-dimensional image of Princess Leia. Luke<br >watches spellbound as the ghostly sculpture of<br >light begs for someone named Ben [Obi-wan]<br >Kenobi to come to her assistance. The image is a<br >hologram， a three-dimensional picture made<br >with the aid of a laser， and the technological<br >magic required to make such images is remark-<br >able. But what is even more astounding is that<br >some scientists are beginning to believe that the<br >universe itself is a kind of giant hologram， a<br >splendidly detailed illusion no more or less real<br >than the image of Princess Leia that starts Luke<br >on his quest.<br > Put another way， there is evidence to suggest<br >that our world and everything in it are only<br >i<br >