Wikipedia is a great starting point for learning about your artist. Use the links at the bottom of your artist's Wikipedia page to find more websites about your artist.
Art Cyclopedia includes over 9000 artists.
The CHSE Library has many art books in the nonfiction and reference sections. Use the CHSE Library Catalog to search for books about your artist.
The Museum of Latin American Art website lists over a hundred artists, and provides information about their work.
The WebMuseum Paris website includes biographical information about hundreds of artists and also provides examples of their work.
Artlex Art Dictionary is another excellent resource for information about your artist.