All over the world, libraries have begun the Herculean  task of making faithful digital copies of the books, images and recordings that preserve the intellectual effort of mankind. For armchair scholars, the work promises to bring such a wealth of information to desktop that the present Internet may not match. Librarians see three clear benefits to going digital. First, it helps them preserve rare and fragile objects without refusing the demands of those who wish to study them. The British Library, for example, holds the only medieval manuscript of Beowulf in London. Only qualified scholars were allowed to see it until Kevin S. Kiernan of the University of Kentucky scanned the Manuscript with three different light sources and put the images up on the Internet for anyone to use. A second benefit is convenience. Once books are changed to digital form, readers can find them in seconds rather than minutes. Several people can read the same book or view the same picture at the same time. Clerks are spared the chore of reshelving. And libraries could use the Internet to lend their collections to those who are unable to visit in person. The third advantage of electronic copies is that they occupy millimeters of space on a magnetic disk rather than meters on a shelf. The cost of library buildings is increasingly high. The University of California at Berkeley recently spent $ 46 million on an underground addition to house 1.5 million books----an average cost of $30 per volume. The price of disk storage, on the contrary, has fallen to about $ 2 per 300-page publication and continues to drop. How is the text organized?
Opinion - Description Message - Explanation Main idea - Comparison Introduction - Conclusion