The article looks back at the development of digital libraries, focusing on a number of key projects before turning to the commercialisation of digital books. E-book producers have come up with formats that prevent illegal copying and create a captive audience. The author argues in favour of open formats that allow the reader to use different devices and software, rather than proprietary formats that force the reader to use one sole provider. DRM, or Digital Rights Management, is a form of information held in e-books that prevents all kinds of copying, including legal copying for private use. DRM also allows companies to implement monopolistic commercial practices. These aspects mean that it is difficult to integrate such works into the library system.