In Chapter Three of Why We Can't Wait, King depicts Bull Connor's Birmingham as a place that embodies virtually every evil of segregation. It is a place where the vast majority of African-Americans cannot vote, obtain decent jobs, send their children to good schools, obtain justice in the courts, or anything else that Americans associate with the benefits of living in a "free" and prosperous country. Birmingham was, in short, "the most segregated city in America." It was also, however, a city with a strong black dissident presence, in the form of the Alabama Christian Movement for Human Rights, led by local minister Fred Shuttlesworth. King relates how the Southern Christian Leadership Council, his organization, determined to wage a campaign of direct action against segregation in the city. The rationale was that a success against such a segregation stronghold as Birmingham had the potential to "break the back" of Jim Crow throughout the South. Plans were made for a demonstration against downtown stores, but they had to wait until the aftermath of a run-off election for mayor between Connor and Albert Boutwell.
Source: Martin Luther King, Why We Can't Wait (Boston: Beacon Press, 1963) 47-61.