A useful, and constantly developing resource is Wikipedia, the free encyclopedia. This is multi-authored and therefore to be used with caution, but does give helpful, if brief, introductory summaries on a surprisingly wide range of topics (with versions in languages other than English). The current version of the Encyclopedia Britannica was originally released onto the web without charge but its useful articles are now available only on subscription. However, 'over 57,000 articles' from the 6th Edition of the Columbia Encyclopedia can be accessed free of charge via HighBeam, while Bartleby.com links to 'nearly 51,000 articles'. Bartleby.com also provides access to the Encyclopedia of World History (a 'comprehensive chronology of more than 20,000 entries' by Peter N. Stearns), the Columbia Gazetteer of North America, quotations, Shakespeare's works, etc., and a wide range of out- of-print texts.

For historical encyclopedias the following are online:

• Ephraim Chambers, Cyclopaedia, or, An universal dictionary of arts and sciences (1728) (University of Wisconsin Digital Collections)
• LoveToKnow Free Online Encyclopedia (what appears to be the full, searchable text of the much-respected 11th edition (29 volumes, 1911) of the Encyclopaedia Britannica - though, not surprisingly, without illustrations - to which they are 'adding entries on new relevant topics')

Italian readers can consult 'Mondi di carta' (encyclopedic entries, with links to other similar compilations in Italian, from sapere.it).

For biographical information see the People links.