When researching an individual work of art, the museum of origin is usually the best place to start, as they will likely have the most information on their own collection. The Art Institute of Chicago has an excellent online database of the collection. Search for your work and see if they provide any information or a bibliography of further publications that discuss your work, called the "Publication History" section.
As you are starting to explore a new research topic, reference sources are a good way to gain background information on your topic. High quality, academic, multivolume sets, will often give you the beginnings of scholarly research on a subject by providing a short bibliography of important works on the subject.
Even with advanced subject knowledge of an area, you will run across unfamiliar people, places and events. Library reference sources will allow you to quickly fill in those gaps and improve your contextual knowledge with more reliability than a Wikipedia article.
We have several books in our reference collection and in the stacks that might provide basic biographical information on your artist. Some of these have bibliographies that can provide further resources for your search.