Biographical dictionaries and encyclopedias provide brief essays on historical figures. They are similar in scope to Wikipedia entries, but are written by authorities in the field. Listed here are only a handful of the major online collection - we have many similiar and more specialized titles in print.
In addition to the biographical databases, try the section on Historical Encyclopedias and Dictionaries. The library also has an extensive collection of print resources - far too many to list here. If you are not finding what you need use the contact information on the left sidebar and ask for help!