The University of Cambridge, with the help of some others, has put nearly all Charles Darwin papers online. The project is named The Complete Work of Charles Darwin Online. These papers include from influential books like the On the Origin of Species, to personal letters, reprints, notes and drawings, etc. No doubt this virtual library will be of help for teachers and students, and why not, for researchers.
As more and more contents in lifbraries and museums are put online, the value of the net increases. This includes, for instance, the virtual visit to the Museo Thyssen in Madrid, or the Biblioteca Virtual Miguel de Cervantes (digital panhispanic library).
But a major criticism to these otherwise valuable works, is their licenses. Fors instance, the license of the Darwin library claims:
The materials found on the Website may not be posted or in any way mirrored on the WWW or any other part of the Internet except at the following publication site: http://darwin-online.org.uk.
What a pity. In fact, I have taken the picture above from a more solidary website, the Wikipedia.