In this tale of one of America's most august institutions, Nelson Polsby argues that among other things, from the 1950s to the 1990s, Congress evolved. In short, Polsby argues that air conditioning altered the demography of the Southern States, which in turn changed the political parties of the South, which transformed the composition and in due course the performance of the US House of Representatives. This evolutionary process led to the House's liberalization and later to its transformation into an arena of sharp partisanship, visible among both Democrats and Republicans. This book breathes new life into the dusty corners of institutional history, and offers an explanation for important transformations in the congressional environment.