The telephone rang after midnight and sleep was not an option for the Rev. Martin Luther King, Jr., after he answered it.

It was late 1956. Years later, King quoted that hellish voice: "Nigger, we are tired of you and your mess now. And if you aren't out of this town in three days, we are going to blow your brains out and blow up your house."

King ended up in the kitchen, meditating on the mystery of evil and worrying about his family. He began praying out loud, voicing his feelings of weakness, frustration and fear. Soon, he fell into a waking dream in which God gave him comfort and courage. He glimpsed the future.

The next day, King told reporters: "I had a vision."

This became a touchstone event and shaped one of his signature themes. But the wording had changed by the time King reached the Lincoln Memorial on Aug. 28, 1963.  By then the voice of the Civil Rights Movement was crying out: "I have a dream."

Four decades later, this speech may be the only exposure that millions of young Americans have ever had to King's preaching and writing, said Drew Hansen, author of "The Dream," a new book that offers an in-depth analysis of the history and content of the speech.

This is sadly limited view of a complex man and his times, said the 30-year-old Seattle lawyer. But many who watch or read this speech may be inspired to learn more. After all, that is what happened to Hansen during a Yale Law School class on civil rights. He dug deeper and what he found was both inspiring and sobering.

"It's easy to focus on this speech and King's victories and all those barriers that fell back in the days when things were so bad," said Hansen, an evangelical Christian who graduated from Harvard and also studied theology at Oxford University.

"Focusing on this speech alone is certainly a lot easier than meditating on all of the barriers that remain. ... But still, this is a wonderful place to start as we give King the homage that is his due as a preacher, public philosopher, field general and prophet."

It is crucial to grasp the context. Hansen noted that King traveled about 275,000 miles and delivered at least 350 speeches during the year of the March on Washington. Witnesses said he worked on the text up to the last minute, literally marking out passages and scribbling in others as he sat waiting to speak.

Hansen's book includes material from rough drafts prepared by aides as well as a side-by-side comparison of the text as King wrote it and then delivered it. This includes detailed descriptions of the preacher's vocal inflections and use of dramatic pauses and repeated sentence constructions that let his listeners to respond to his words like skilled jazz musicians.

"King knew how to read his audience," said Hansen. "That had been part of his training since he was a little boy in his daddy's church. This address was a case of a talented preacher getting caught up in a call-and-response experience, not just with the audience in front of him, but with the whole nation. "That's why these words touched people then and they touch people now."

It was supposed to have been a political speech. Yet nearly every significant metaphor in it can be traced to a biblical source, noted Hansen. Growing up in black Baptist churches, King had been baptized in the words, grammar and imagery of the King James Bible. This provided a solid foundation as he spoke to African Americans and, ironically, to white Protestants in the Deep South. King knew that the Bible had authority --authority to inspire and to judge.

This is what King turned to as he faced the nation. The entire "I have a dream" section of the speech was not in his written text.

"He wrote a political address," said Hansen. "It's not that other people wrote a political address for him. King's own draft was nothing like a sermon. But the speech he actually delivered was not dominated by that kind of political language. He left lots of that out and everything he added was rooted in biblical images and themes. That changed everything."