In addition to the Illinois and Federal resources listed here and the databases provided, be sure to explore the Communities of Practice page since it offers links to several very large information portals.
The Legislative Research Unit (LRU) was established in 1937 to provide object research for members of the Illinois General Assembly and their staffs. Several key publications are available to the public on this page. http://www.ilga.gov/commission/lru/lru_home.html
Topic areas include: Business Regulation, Criminal Law, Education, Families, Government, General Assembly, Health and Safety, Revenue, Transportation.