With Mrs. Kennedy, it’s a different story. Manchester may hymn the First Lady’s looks and elegance, but in her he has a living—indeed, suddenly metamorphosing—creature to deal with. After the killing, immune to Scotch and sedatives, she marshals her will for a series of history-minded decisions and truly graceful gestures (gently touching the ham hand of the weeping Sergeant Dugger, for one). Manchester makes plain that Bobby Kennedy, not his sister-in-law, took the initial steps toward planning the massive state funeral. But once Mrs. Kennedy rose to full function, the two of them became a formidable team.

In 1966 they united against Manchester, attempting to thwart serialization of The Death of a President in Look magazine, and then to block publication of the book itself by redeeming the author’s early, unwise promise of “manuscript approval.” In Mrs. Kennedy’s case, Manchester realized, the basic problem was that “she didn’t really want any book” at all on the assassination, especially one that had been enabled by her long, daiquiri-driven interviews with the author. When she met with Manchester to hash things out, she deployed “tears, grimaces, and whispery cries of ‘Jesus Christ!’,” as well as a threatening reminder that the only thing the American public wouldn’t put up with from her was running off with Eddie Fisher.

Bobby Kennedy’s objections followed a political calculus that now seems obscure. Not yet having decided to run for president, he was afraid that Manchester’s depictions of Lyndon Johnson—first as a humbled vice president and then, suddenly, an overeager chief executive—might create problems for himself inside the Democratic party. Evan Thomas, Manchester’s editor at Harper & Row (and father of RFK’s subsequent biographer), proposed a bundle of cuts and changes, not only to please the Kennedy family but to keep Harper & Row from losing a crack at LBC’s own memoirs when the time came for them to be auctioned.

Any reader of the battle scenes between the Kennedy “loyalists” and Johnson “realists” will understand that Manchester’s portrait of Johnson is in fact so fundamentally reasonable and sympathetic—it shows a man marshaling his huge skills during what, for all anyone knew, might be an international plot preceding a nuclear attack—that it has to have been largely that way from the beginning. On the other hand, those in the Kennedy camp (including, occasionally, RFK himself) behaved so disgracefully that one must wonder if Bobby’s real fear wasn’t what readers would think of them. In this sense, Robert Kennedy’s attempt to suppress Manchester’s book seems only an extension of the grief-entitled arrogance on display that weekend.

At the beginning of this decade, I made my own foray into the history of the assassination with a long profile for The New Yorker of Ruth Paine, the Quaker woman in Dallas who became a key Warren Commission witness because of her solicitous friendship with Lee and Marina Oswald. In the nine months before Kennedy’s murder, Ruth helped Oswald to get his job at the Book Depository and remained unaware that he was keeping a rifle in her garage.

A poignant figure whose life was convulsed by her connection to the killing, she left Manchester, as he put it in a footnote, “impressed by her exceptional forthrightness.” He sought her out primarily for help in understanding Oswald’s behavior. When I tracked Ruth down decades later, it was not in order to reinvestigate the crime (I am an implacable Lone Nutter), but with a view toward understanding her own character and ordeal. Among my many sources were Manchester’s book as well the notes from his interview with Ruth, now in the National Archives.

I have come to realize that Manchester’s approach—his quest for the smallest particulars, his emotional sense of history and its ironies—informed my work more than any specific facts I learned from him. When it came time to publish Mrs. Paine’s Garage (2002), an expansion of my magazine piece, I endured nothing to equal Manchester’s legal and personal ordeal, but I did experience a degree of psychological stress. Ruth’s own agitation about having revisited her awful experience spilled over into my life and, predictably, I had to deal with a bilious bubbling up of scorn from the still feverish swamps of conspiracy theory.

Thomas Mallon is a frequent contributor to The New Yorker, The Atlantic, and many other magazines, and the author of seven novels and six works of nonfiction.