By John Blake, CNN
(CNN) - By the time Clarence Jones reached him, the Rev. Martin Luther King Jr. was in bad shape.
He was unshaven, dirty and dejected. King had spent several days alone in solitary confinement with no mattress in a filthy dark jail cell in Birmingham, Alabama.
"Take this out of here," King whispered as he grabbed Jones' belt and stuffed bawled-up newspapers and toilet tissue down his pants.
Jones, King's lawyer, wondered if King was starting to lose it. He didn't pay attention to what King had given him - it was just a mish-mash of words and arrows scribbled on bits of paper.
"Not until five days later did I actually read a mimeographed copy of the letter," says Jones. "To be honest with you, I was more worried about bail money, not what he had written."
Millions of people have since read what Jones first ignored. As the nation commemorates the 50th anniversary of King's "Letter from Birmingham Jail" on Tuesday, the document has become an American epistle. It's considered a classic defense of civil disobedience.
But those who see King's letter as just a tract on nonviolent resistance make the same mistake King's lawyer made: They miss what's special about something that's right in front of their eyes, some King scholars say.
The letter is one of the most intimate snapshots of a King most people don't know: An angry black man who once hated white people and, according to one scholar, was more dangerous than Malcolm X, a man King admired.
"Before everything else, (the letter) is a black man's cry of pain, anger and defiance," says Jonathan Rieder, author of the just-released "Gospel of Freedom," which looks at the "furious truth teller" revealed in King's classic letter.
King's blackness - his fierce racial pride, his distinctively black Christian faith and his belief that most whites were "unconscious racists" - is on full display in his letter, scholars say. The anger that drove King's letter would become more prominent in the speeches King gave until, literally, his last hours, Rieder says.