To understand Africa, one must understand Nigeria, and few Americans understand Nigeria better than Karl Maier. This House Has Fallen is a bracing and disturbing report on the state of Africa’s most populous, potentially richest, and most dangerously dysfunctional nation. Each year, with depressing consistency, Nigeria has been declared the most corrupt state in the entire world. Though Nigeria is a nation into which billions of dollars of oil money flow, its per capita income has fallen dramatically in the past two decades. Military coup follows military coup.