DESPITE THE COVER photograph of the Rev. Martin Luther King Sr., mouth open and shouting, Daddy King is a thoughtful book. For those who recall the old Baptist preacher bellowing out the benediction at the 1976 and 1980 Democratic Conventions, the reflective quality of this autobiography may be a surprise.

Readers who turn to Daddy King primarily to trace the roots of Martin Luther King Jr. may also be surprised to discover that his father's story is fascinating history in its own right

What caused such self-confidence in the grandson of slaves, son of illiterate sharecroppers, a man of 20 sent back to the fifth grade when he sought an education in Atlanta, that he could later write, "It never did enter my mind that I wouldn't become successful"?

What other father has had his elder son win the Nobel Peace Prize and then be assassinated, his only other son die in a mysterious drowning, and his beloved wife of nearly 50 years shot down in front of him while playing "The Lord's Prayer" on the church organ? What other American family has risen so high and been struck down so far?

The Kennedys come to mind. On reading about Daddy King's vehement anti-Catholicism, John Kennedy once remarded: "Imagine Martin Luther King having a bigot for a father!" Then with a grin Kennedy added, "Well, we all have fathers, don't we?"

We don't all have fathers like theirs.

Some of the women who married Kennedy sons may feel kinship with Coretta Scott when they read of the young Antioch graduate's first meeting with her formidable future father-in-law. Opposing her marrying his son, Daddy King -- "stubbornly, with that old country mule rising up in me" -- told her that "M.L. has gone out with daughters of some fine, solid Atlanta families . . . people who have much to share and much to offer." Coretta replied cooly, eyes flashing, "I have something to offer, Reverend King." On parting, Daddy King told her that if M.L. was convinced, "I was sure that eventually I would be." He adds, "And, eventually, I was."

Yet, like Joe Kennedy, Daddy King was at his son's side, or behind him, at most critical junctures. After the firt bombings in Montgomery, he did his best to keep his son from going back to an inevitable prison sentence. When all arguments failed, however, it was Daddy King who got up at dawn to drive Martin and Coretta from Atlanta into the maelstrom at Montgomery.

Unlike Joseph Kennedy, Daddy King lived on after his sons -- to see a granddaughter elected to the Georgia state legislature, to himself be invited to address a joint session of the Alabama state legislature, to have George Wallace ask him to pray for him, and, with Coretta and Andrew Young, to play a major part in swinging the crucial black vote to Jimmy Carter during the primaries of 1976 and 1980.

Daddy King was written in collaboration with Clayton Riley, but whatever Riley's contribution, the result is a fast-moving narrative in which King speaks very dirrectly and simply in his authentic voice. Martin Jr. could reach heights of rhetoric in his writing, yet when he wrote anything personal he tended to be ponderous or stilted. Not so his father, who at age 81 tells his tale with few frills and much candor.

What a story it is! One of 10 children, Mike King (as his family knew him) was licensed as a country preacher at age 15. By then, at close range, he had seen a black man lynched by whiskey-drinking whites, and himself had been kicked and bloodied by a white mill owner. The journey of Martin Jr., 30 years later, seeking his PhD in the North, pales by comparison to his father's odyssey in the Deep South in the second decade of this century. In 1941, at age 15, Martin Jr. skipped his last year in the Booker T. Washington High School and was admitted to Morehouse College. In 1912, there was no high school for blacks in Atlanta; at age 14, Martin Sr. was shoveling coal in a locomotive where the firemen thought of him "as a young bull who could make steam and be a good nigger, too." Daddy King recalls, "I thought about the money, and I let them think whatever they wanted to."

King also thought about education. In the one-room shack where he had gone to school in the country, he had been teased for smelling like a mule. He might smell like a mule, he answered, but he would never think like one. He credits his elder sister for getting it through his "stubborn head" that there was nothing you could do without an education.

A harder thing to get through his head was the idea of loving his enemies. At his mother's death bed, he "cursed whites" who had brought so much pain to her and swore he would "hate every white face I ever saw," but she made him promise not to do that. "Hatred," she told him, makes nothin' but more hatred. . . . Don't you do it."

He claims to have kept that promise. But when his student son Martin helped form an integrated Intercollegiate council, the skeptical father said, "I don't like it, M.L. You don't need to risk any betrayals from them, and that's mainly what you'll get." To forget "the fundamental decency of whites," Martin Jr. argued, "was simply to become the very people we've been fighting against."

At age 81, Daddy King is glad his son "made his point . . . and had given his stubborn old father new food for thought." Tempered by tragedy, Daddy King completed his journey to nonviolence. Presiding over a three-hour family dialogue after his wife was killed, he listened to the young ones ask, "Why did God let that crazy man kill Big Mama? Why do all these terrible things happen to our family? Finally, he said that however hard it was to understand, "God wants us to love one another. . . . Now get out of here, and remember: Don't ever stoop so low that you let anybody make you hate."

In the end, Daddy King even pokes fun at his old shouting ways. He boasts that now, instead of trying just to move people, he preaches to make people think. In his life story, he succeeds in doing both.