The 2009-2010 State of Wisconsin Blue Book is now available on the Legislative Reference Bureau website.
Past editions of the Blue Book (1995-2008) are also available on the LRB sites. Older editions (1853-2004) have been digitized and made available by University of Wisconsin Digital Collections.
From the UWDCC site:
The State of Wisconsin Blue Book remains the primary one-volume reference source about the state, documenting the organization of the state’s three branches of government (legislative, executive, and judicial).
Typically, each volume includes extensive description and statistics on virtually all aspects of life in Wisconsin, including major sections on the state’s population, geography, history, election data, educational resources, social services, finance, agriculture, industry, transportation system, etc. Various useful lists are also provided, such as of statewide associations, news media, local governmental units, post offices, political parties, etc.