What is the theme in Rising Tide: The Great Mississippi Flood of 1927 and How it Changed America by John M. Barry?

Racial inequality is a major theme in the book. The book chronicles not only the flood itself, but also the aftermath, including rescue and rebuilding efforts. The rescue efforts take place over several months, nationally, with operations lasting up to several weeks in any particular locale. The rebuilding efforts include national, regional, state and local efforts, which continue for several years.