Rat City: Overcrowding and Urban Derangement in the Rodent Universes of John B. Calhoun - Hardcoverby Jon Adams (Author), Edmund Ramsden (Author) Behind the internet's viral "Universe 25" experiment and Robert C. O'Brien's iconic novel, Mrs. Frisby and the Secret of NIMH, was one scientist who set out to change the way we view our fellow man using rats . . . After the Civil War and throughout the twentieth century, cities in northern American states absorbed a huge increase in populations, particularly of immigrants and African Americans from