On April 16, 1963, days after being jailed in Birmingham, Alabama, for a series of anti-segregation protests, Dr. Martin Luther King, Jr. pens a response to his critics on some scraps of paper. This open letter, now known as his “Letter from a Birmingham Jail,” offered a forceful defense of the protest campaign. It is now regarded as one of the greatest texts of the American civil rights movement.

First circulated as a mimeographed copy around Birmingham, King's letter was later published in numerous places. It appeared as a pamphlet from the American Friends Service Committee, and in publication as diverse as Ebony, Christian Century and The New York Post. Part of it was introduced into The Congressional Record as part of testimony by New York Congressman William Fitts Ryan. And King revised it as a chapter of his 1964 memoir Why We Can't Wait.

The letter was addressed to eight white “Fellow Clergymen” who had criticized the protest campaign in a joint statement published on April 13 in the Birmingham News. King first dispensed with the idea that he, as a preacher from Atlanta was too much of an “outsider” to confront bigotry in Birmingham, saying, “I am cognizant of the interrelatedness of all communities and states. I cannot sit idly by in Atlanta and not be concerned about what happens in Birmingham. Injustice anywhere is a threat to justice everywhere.”

While stressing the importance of non-violence, King rejected the idea that his movement was acting too fast or too dramatically: “We know through painful experience that freedom is never voluntarily given by the oppressor; it must be demanded by the oppressed. Frankly, I have yet to engage in a direct action campaign that was ‘well timed’ in the view of those who have not suffered unduly from the disease of segregation.” King also advocated for violating unjust laws and urged that believers in organized religion “[break] loose from the paralyzing chains of conformity.”

All told, the lengthy letter constituted a defense of nonviolent protest, a call to push the issue of civil rights, and a rallying cry for fence-sitters to join the fight, even if it meant that they, too, might end up in jail.

The Birmingham campaign succeeded in drawing national attention to the horrors of segregation. After the United Auto Workers paid King’s $160,000 bail, he was released from jail on April 20. Four months later, he stood on the steps of the Lincoln Memorial and gave his “I Have a Dream” speech at the March on Washington for Jobs and Freedom, regarded by many as the pinnacle of his movement.