It seems appropriate to say something about him.
One of the greatest failures in my schooling, and there were many, was that I wasn't introduced to the Letter from Birmingham Jail until after I could have graduated college. I was, as I recall, sticking around to get a double major instead of a major-minor combo when I met the letter in a Greek tragedy class of all places. Because Greek tragedy is about ethics, and the letter is very much about ethics, and ... yeah.
So over at The Slacktiverse I made a thread posting various excerpts of the letter and also a link to the letter in full.
I think everyone should read it, it is well worth reading.
I'm not going to reproduce the Slacktiverse post here because it would be pointless, you can read it there.
Instead I shall sum up.
The letter is an example of how to respond to people who are wrong, but wrong in good faith.
It is important to understand that injustice anywhere to anyone is a threat to justice everywhere for everyone. It is not enough to be concerned about visible unrest, one must also look to the reasons behind it. (Sometimes these reasons will be legitimate, sometimes they will not.) There is a right way to wage a nonviolent campaign. The purpose of demonstration is to get those who refuse to come to the negotiating table to actually show up, it is not something done instead of negotiation, it is something done to cause it. Tensions can be necessary to make the right things come to pass, in fact historically it always has been because in the absence of pressure the privileged do not give up their privilege.
Those who have not been oppressed do not know what it is like, and if they did they would understand why, "Wait," which more often than not means, "Never," is not an acceptable response.
Laws are not all created equal, some are just, others are unjust (and some seem just but can be used to unjust ends) determining between the two is simple, "Any law that uplifts human personality is just. Any law that degrades human personality is unjust." Those who openly break unjust laws and accept the penalties placed upon them are not disrespecting the laws, they're paying them the respect they deserve.
Lukewarm allies can often be more of a hindrance than enemies because, while in theory on your side they give bad advice and impeded progress. They are more concerned with order than with justice, more concerned with not rocking the boat than with fixing what is wrong.
The letter contains strong condemnation of victim blaming. It speaks of the misconception that if one waits things will get better. Things will only get better if people work to make it so, otherwise the other side will use time to make things worse.
Nonviolence provides an outlet for legitimate frustrations and outrage that might otherwise be channeled in violent directions.
Moderates can be labeled as extremists, but the label isn't necessarily wrong. The question is what they are extremists for. Extremists for love are very different than extremists for hate.
Those who should have come to help, by and large, didn't. While the exceptions were notable and laudable they were still the exceptions. When good people did nothing and stood at the sidelines it made the fight for justice much more difficult than it should have been. Of those that were exceptions they risked much and lost much but they "acted it faith that right defeated is stronger than evil triumphant."
On means and ends it isn't enough to have one or the other be good. It is only if good means are used to reach good ends that one is in the right. To have either the ends or the means be evil is immoral.
And so on.
Don't take my word for it. It's all in the letter, and well argued at that. Read the letter.