The conclusion of Dr. King's letter can be thought to be comprised of the final three paragraphs. When he begins the conclusion, King begins the third-to-last paragraph with the words "Never before have I written so long a letter." By referring specifically to the letter itself, King is marking a transition from the content of his argument to his final thoughts and words. At this point the letter departs from King making claims of fact, value, and policy, and his tone shifts from that of a crusading activist to a man speaking directly to his audience about what his intention has been in crafting the argument.

The introduction of the letter can be thought to be comprised of the first twelve paragraphs. In them, King first explains why he is writing the letter, and why he is in Birmingham in the first place. He is answering a letter signed by local clergyman who claim that King's demonstrations are "unwise and untimely" and imply that he is an outside agitator who needs to leave and let the area officials resolve the issues at hand. King rebuts the idea that he is an outsider, because he believes that it is his job to address social injustice wherever it occurs. He outlines, in these opening paragraphs, what he and his followers are attempting to accomplish and their reasons and methods for doing so. The introduction is an assurance that he is not in Birmingham to create trouble or incite violence.

The rest of the body paragraphs constitute the "middle" of King's letter. In it, he lays out a reasoned argument with appeals to ethos, logos and pathos, using rhetorical techniques including anecdote, analogy, firsthand and secondhand evidence as well as concession and refutation, to build his argument that the civil rights of African Americans must be fully and freely granted in the country.

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I would suggest that the introduction to the Letter from Birmingham Jail contains five paragraphs, concluding with "it is even more unfortunate that the city's white power structure left the Negro community with no alternative." These paragraphs provide the background, the historic developments that led to his actions in Birmingham.

I count 41 paragraphs in the body of the letter; the detailed recounting of the basis for the actions taken, the encounters with other groups, the reaction and lack of action experienced at numerous points, the determination of new tactics brought about by the perceived need to create change in new ways since old practices were proving ineffective, the justification of measures taken and attempts to reconcile those measures with opposing viewpoints, the expression of frustration, disappointment, and hope.

The concluding three paragraphs apologize for the length of the letter and express hope for future opportunities.

I think that the number of paragraphs is going to be a relative concept.  With the transmission of speeches and writings to the web, strict paragraphing entirely followed.  We can trace the structure of Dr. King’s letter in specific terms, though.  The introduction to the letter consists of the opening address to whom King refers in the assertion that King and his followers’ actions were “unwise and untimely.”  In reference to other organizations, the introduction comes to a close.  I would say that the middle begins with the idea that Dr. King is in “Birmingham because injustice is here.”  This helps to launch him into an explanation of the cause and the need to fight for social justice.  This “middle” goes on for quite a bit.  For my bet, the conclusion of the letter begins with the simple sentence, “I must close now,” as Dr. King concludes in demanding that all members of society- White and Black- fully heed the call for social equity and to hear the cries of others’ sufferings in making Southern society, and in turn all of America, recognize its promises and possibilities in creating a system of equal treatment for all.