Over the years, America's national elections have become focused almost exclusively on Democrats and Republicans; other parties exist but rarely rise to prominence. Elections at the state level, on the other hand, offer a livelier history, with successful candidates from political parties of all stripe, including Free Soil, Abolitionist, Anti-Monopoly, Farmers Alliance, War Democrat, Anti-Masonic, Socialist, and many more.

This book lists the party affiliation of state legislatures beginning in 1796 through the elections of 2006. Information on each state includes a summary of how its electoral process developed, including the origins and stipulations of each state's constitution, the terms and size of the legislature, and other details pertaining to the history of the state's legislative branch. Each state's chapter closes with a list of sources. In all, the book documents over 100 different party affiliations.