What Jack and Jo Ann Hinckley have written, with the highly professional assistance of Elizabeth Sherrill, is a sad and cautionary tale that addresses itself to the dark side of the American dream. We all know, before reading its first page, that it is the story of a prosperous American husband and wife who learned one awful day in 1981 that their youngest child had attempted to murder the president of the United States. More than that, though, it is the story of how the Hinckleys' obsessive pursuit of "success," as it is conventionally defined in this country, had blinded them to their son's deteriorating mental state and desperate need for help.

Though it certainly has the potential to be, "Breaking Points" is neither a self-pitying nor a self-dramatizing book. With impressive candor and a courageous willingness to face up to the hard truths about themselves, the Hinckleys describe the self-absorption that distanced them from their son John, the disagreements over parental responsibilities that complicated their efforts to help him, and the persistent failures of communication between parents and child, husband and wife. "Breaking Points" is tough and unsparing, and it should have a good deal to say to other parents who find themselves puzzled and dismayed by difficult, recalcitrant children.

Because the Hinckleys were so widely and reflexively vilified in the months after the assassination attempt, it somehow seems necessary to say that they are good people. They are not rich, complacent right-wingers or preachy, self-righteous religionists, but decent, hardworking people whose persistent labors over many years seemed to have paid off handsomely. They rose from relatively unprepossessing beginnings in Oklahoma to considerable wealth, thanks to Jack Hinckley's efforts in the oil trade, and residency in affluent neighborhoods of Dallas and Denver. Theirs was an American success story.

They believed, as do millions of other Americans who remember the Depression and the wartime recovery from it, that the solution for everything is hard work. "Give it all you've got" was Jack's "watchword"; he believed that "determination could accomplish anything -- hadn't it won the war?" So when their youngest child started to go astray, their natural response was to tell him to get cracking, get going, put his nose to the grindstone: The business of America is business, kid, so get at it.

Quite literally, they threw him out. Though Jo Ann silently resisted it, Jack's stubborn insistence that what had been good for him would be good for his son carried the day. After one more instance of John's erratic behavior than he could tolerate, Jack met him at the Denver airport. As he testified at his son's trial: "I told him how disappointed I was in him, that he had left us no choice but not to take him back to the house again . . . I suggested that he go to the YMCA and he said no, he didn't want to do that. And so I said, 'O.K., you are on your own. Do whatever you want to.' "

It was, Jack, believes, "the greatest mistake of my life," but it is not really surprising that he made it. Like so many American parents, he had failed to perceive his child's real life because he had been so caught up in his own drive for success and conventional respectability. A silent kid who listened to Beatles records in his room and yearned for a career in rock music was beyond Jack's experience and comprehension, so he simply dismissed him. He gave time and money to relief agencies trying to alleviate hunger abroad, but:

"The possibility that someone was hurting much closer by, right beneath our own shake-shingled roof, did not occur to me. Of course I knew John was having his problems -- but with enough effort and self-discipline he'd lick them. My whole activist, achiever philosophy blinded me to needs that weren't visible. Drought, famine, unjust social conditions -- they were enemies we could see and tackle."

This alone does not explain why John Hinckley drifted off into a world of fantasy and self-hatred, a world from which he emerged to shoot Ronald Reagan, James Brady and two other men, but it certainly was an important part of the process. Both Hinckleys now fully understand their unwitting complicity in their son's deterioration; they write about it with a candor that is genuinely painful, yet never mawkish or self-serving. From this terrible experience they have learned a great deal about mental illness and the various forces, both internal and external, that produce it; their purpose in writing the book is not to exploit their own suffering, but to help others avoid it.

In their story there is much that is already familiar -- Jodie Foster, "Taxi Driver," John's attempts at suicide, the insanity defense -- and that needs no further elaboration here. But two points must be made. The first is that in their steadfast loyalty to their son both Hinckleys set an example that should be the envy of all other parents. It would have been easy enough for them to say that the kid had gone off his rocker, that he'd been thrown out of the house, that they'd done all they could and felt no further obligation to him; many other parents would have done precisely that. Instead they stood by him faithfully, visiting him at every opportunity, pressing his defense, supporting him in every possible way at great financial and emotional cost. They describe all of this without any evidence of pride, but what they did is remarkable.

The second point is that the Hinckleys were cruelly abused by the press. Their celebrity was accidental and unsought, yet they were hounded as though they were movie stars or were accused of murder. The terrible grief and pain they felt were compounded over and again by reporters and photographers who chased them ceaselessly, violated their privacy with impunity, treated them as if they themselves were somehow part of the assassination attempt. That they write about this with as little bitterness as they do is further evidence of the decency that permeates this book -- evidence the press should contemplate with embarrassment and regret.