Until recently, the changed production, distribution, and economic structures made possible by the conversion from paper to digital technologies could be only partially applied to books because, while transporting and warehousing paper books is cumbersome, the paper works exceptionally well once it gets into a reader's hands. This has meant that libraries have been understandably reluctant to change their approach to book collections. However, two technologies will soon allow the full potential of digital technologies to be applied to books. The first is the development of reading machines, or e-readers. Although not everyone is enthusiastic, many people find that the current capabilities of reading machines to be an acceptable, and sometimes very satisfactory, alternative to the paper book. The second technology is print-on-demand. The ultimate expression of this technology is the Espresso Book Machine, which creates paper books quickly and cheaply one at a time.