The Wisconsin Blue Book is one of my favorite resources for state specific data.
It is often a go-to resource when trying to find statistics. However, what if you are looking for information on all 50 states? Check out the Book of States, a reference tool published by the Council of State Governments.
The Book of States consists of 10 chapters covering such topics as state constitutions, elections, state finance, state management, administration and demographics, as well as the three branches of government. Each chapter contains a variety of facts and statistics. The publication includes more than 150 different tables, each available via PDF or XLS. In addition, each chapter contains several articles on current issues facing state government.
Need historical data? The CSG has placed the entire archive of the Book of States, dating to 1935, online. It should be noted that until 2002, the Book of States was a biennial publication.