Wikipedia is a free online encyclopedia that anyone can edit. It is an excellent source for getting background knowledge for a topic and a good place to start your research. Looking at the references, footnotes, and suggestions for further reading at the bottom of the page can lead you to primary and secondary sources on the topic.
While a 2005 study in the journal Nature found that "the level of accuracy approached Encyclopædia Britannica's," users should keep in mind that anyone can edit articles. Cross-checking facts, looking at the quality of sources cited by the writers/editors, and reading with a critical eye are strategies determining the validity of the information presented