When a writer is born into a family, the Polish poet Czesław Miłosz said, that family is finished. Yes, but when a writer dies that family’s troubles have only just begun. Wills may be contradictory and instructions to literary executors confused. Works left behind on computers or in desk drawers may be of uncertain status: were they intended for publication or not? And if the writer is famous enough, there’ll be biographers to deal with: can they be trusted to paint a kindly portrait? In their lifetime, authors have a measure of control. Once they’re gone, it’s left to others to guard their reputations.

The vigilance can be fierce, with the appointed custodians (whether spouses, children, lawyers, agents, editors or friends) not so much keepers of the flame as dragons guarding a cave. Posterity is rarely kind to them: however they act, they will be accused of acting badly. If they deny the author’s wishes, as those acting for the French philosopher Michel Foucault have recently done by consenting to the publication of a book he hadn’t finished and didn’t want to come out, they will be called treacherous. And if they are overly loyal, destroying work the author disowned but that deserves to be saved, they will be called philistine or just plain stupid. Either way, they can’t shirk the role allotted them. They have an estate to manage: an acreage of words.

Facebook Twitter Pinterest Harper Lee signed her will only eight days before her death in 2016. Photograph: Chip Somodevilla/Getty Images

Literary management is back in the news because the will left by Harper Lee has been made public. It was signed only eight days before her death in 2016 and, while naming as heirs her niece and three nephews, appointed the lawyer Tonja Carter as her literary executor. Lee’s sister, Alice, used to perform that role, but after Alice’s death in 2014 at the age of 103, Carter assumed control. It was she who discovered the “lost” manuscript of Go Set a Watchman in a safe deposit box and, two months after Alice’s death, arranged for it to come out, despite Lee having maintained for 55 years that To Kill a Mockingbird was the only novel she would ever publish. There has since been talk of a possible third book, though Carter – who opposed the unsealing of the will – hasn’t shed much light on that. There are some in Monroeville, Alabama, Lee’s hometown, who questioned how competent the writer was when she signed the will (“poor Nelle can’t see and can’t hear and will sign anything put before her by anyone in whom she has confidence,” Alice once said). A state of Alabama investigation found that she was not a victim of elder abuse. However, there are many outside Alabama who question how responsibly Lee’s legacy is being managed.

If book burning stems from anger, however misguided or orchestrated, manuscript burning stems from fear

The worst mismanagement in literary history was of Byron’s unpublished memoirs, which became an issue as soon as the news of his death in Missolonghi reached London. The three key players – or culprits – were his friend John Hobhouse (politician and pamphleteer), his publisher John Murray (in whose house in Albemarle Street they gathered) and the Irish poet Thomas Moore (to whom Byron had given the memoirs some years before). Hobhouse was for destroying the memoirs at once. He deeply resented Byron entrusting them to Moore rather than to himself, and he’d heard they were obscene: for the sake of Byron’s reputation, and to spare the feelings of his half-sister Augusta and estranged wife Annabella, they should never see the light of day. Moore disagreed. He’d not only read them but had arranged for a second copy to be made (the original having become dog-eared after passing through so many hands); they were far less offensive than rumour suggested, he said. Murray sided with Hobhouse: he’d made a handsome profit from publishing Byron’s poems but had had a deal of trouble over them (threats, libel suits, angry complaints) and feared the memoirs would bring more. A possible compromise was discussed – to preserve the manuscripts but lock them away for many years. But when this was ruled out, Moore, outflanked, lost heart. And when Murray’s son appeared, by prior arrangement, to help with the burning of the manuscripts, Moore’s protests went unheeded. Within minutes, both the original and the fair copy were ash.

If book burning stems from anger, however misguided or orchestrated, manuscript burning stems from fear. Better to destroy the evidence than to allow it to get into the “wrong” hands. Even now, in a supposedly confessional age, the potential for vicarious outrage is enormous; it’s only the list of offences that has changed. Where illegitimacy, alcoholism, humble social origins or a history of mental illness might once have been cause for shame, these days it’s racism, misogyny, political extremism and sexual abuse. Günter Grass was attacked when it emerged, in his late 70s, that he’d once been a member of the SS, a fact he’d carefully hidden for decades. To his credit, it was he who came clean. The controversy would have been greater (doubtless with calls to strip him of his Nobel prize) if a journalist or biographer had been responsible for the exposure. In January, the ugly politics of the French novelist Louis-Ferdinand Céline came under similar scrutiny, more than half a century after his death, when his widow’s lawyer gave permission for his notoriously antisemitic pamphlets from the 1930s to be reissued, with Gallimard set to publish them. Only after protests from Jewish groups and historians, who said that republication “risked sanctifying incitement to murder”, has Gallimard since backed down.

Texts have an immense power to cause pain. As Stephen Fry likes to say: “Sticks and stones may break my bones, but words will always hurt me.” In recent years, many a victim has come forward to complain of injuries inflicted on them, or their family, by a novel or memoir: Karl Ove Knausgaard’s uncle, Michel Houellebecq’s mother, the pianist James Rhodes’s former wife, Hanif Kureishi’s sister, the family at the centre of Åsne Seierstad’s The Bookseller of Kabul – all have complained or sought legal redress. The rights of the written about have never been so angrily asserted. Sometimes whole communities claim victimhood. The residents of Hallencourt in France are unhappy about the portrayal of them in Édouard Louis’s The End of Eddy, with Louis’s mother leading the charge. “It’s not right, what he’s done,” she told a reporter. “He presents us like backward hicks.”

Facebook Twitter Pinterest Cynthia Nixon and Jennifer Ehle as Emily and Vinnie Dickinson in A Quiet Passion … the afterlife of Emily Dickinson was especially vexatious. Photograph: Allstar/Hurricane Films

Even authors who are stalwart in defending their right to freedom of expression may change camps when they are the one in the headlights. “No biography,” writers sometimes tell their executors. George Orwell and WH Auden are among the many who (unsuccessfully) made that request. With old age comes an urge to tidy up one’s affairs – both the business kind (by making a will) and the amorous (by obliterating evidence of indiscretions). Thomas Hardy’s solution to the prospect of an unflattering biography was to write his own “authentic” version before he died, under the authorship of Florence, his second wife. He set out the terms for her in a private memorandum, stipulating that any facts that were “indiscreet, belittling, monotonous, trivial, provocative, or in other ways inadvisable” should be omitted. A few intimates were in on the deception. At one point, Florence (worried she was not up to the task) showed TE Lawrence what she had written, with a view to getting his help. But the truth didn’t fully emerge until a decade after her two-volume Life had appeared. In the meantime, immediately after Hardy’s death, Florence burned whatever letters and notebooks he hadn’t burned himself. When their gardener, Bertie Stephens, offered to help, “she insisted on doing it herself, and after all the papers had been destroyed, she raked the ashes to be sure that not a single scrap or word remained”. With the primary source material destroyed, Hardy’s semi-fictional autobiography/biography could have the status of definitive truth. “What he wished to be remembered would be remembered,” Philip Larkin wrote, and “what he wished forgotten would be forgotten.”

The instrument of destruction was a shredding machine; more than a dozen of Larkin's A4 diaries went into it

Larkin was fascinated by the precedent that Hardy set, imagining “how the smoke billowed across the garden at the back of Max Gate”. When he was dying in 1985, he followed Hardy’s example, asking his companion, Monica Jones, to destroy his diaries, which he called “a kind of great grumble-book”; too ill to do it, she handed the job to his secretary, Betty Mackereth, instead. The instrument of destruction was a shredding machine; more than a dozen A4 diaries went into it, before being incinerated in Hull University’s boiler house; only the covers survived. “I couldn’t help seeing little bits and pieces,” Mackereth confessed to Larkin’s biographer Andrew Motion. “They were very unhappy. Desperate, really.”

Henry James was another who made “a gigantic bonfire” of his archive, thereby observing what he called “the law of not leaving personal and private documents at the mercy of any accidents, or even of my executors!” His sole wish, he said, was “to frustrate as utterly as possible the post-mortem exploiter”, the kind of figure he writes about in his novel The Aspern Papers, in which a “publishing scoundrel” goes to Venice to get his hands on the literary remains of a famous American poet, Jeffrey Aspern, and cons his way into Aspern’s aged former lover’s house. James took up the theme again in his story “The Real Right Thing”. This time, the post-mortem exploiter is less unscrupulous, having been invited by the widow of a famous novelist, Ashton Doyne, to peruse her husband’s papers. As Doyne’s ghostly presence turns disapproving, both widow and acolyte back away, convinced he’s warning them off: the life mustn’t be raked over in a Life.

That authors can exert their influence from beyond the grave is no fiction; just because they are past doesn’t stop them tampering with their future. In his lifetime, Samuel Beckett was careful to police new productions of his plays: stage directions had to be followed to the letter. Since Beckett’s death, his nephew Edward Beckett has done the same. In 1994, he prevented Deborah Warner’s production of Footfalls at the Garrick theatre in London from touring. And he has since opposed the use of music, casting of women and “injection” of race in Waiting for Godot, or imposed bans on them.

As Edward Beckett sees it, he’s doing the right thing by his uncle. But writers are often poor judges of their own work or how to preserve their legacies. Eugene O’Neill doubted the value of several plays he had written; it was only through the efforts of his third wife and literary executor, Carlotta Monterey, that many manuscripts survived – and that his masterpiece Long Day’s Journey into Night (on which he’d placed a 25-year embargo) was produced shortly after his death.

Max Brod denied Kafka's wishes – and without him, The Trial, The Castle and Amerika would not exist today

And then there’s Foucault, the fourth volume of whose major work The History of Sexuality existed only as a first draft when he died in 1984, but has just been released under the title Confessions of the Flesh. “The rights-holders of Michel Foucault considered that the time and the conditions had come to publish this major unreleased work,” the philosopher Frédéric Gros writes in his introduction, though Foucault was clearly opposed. “Pas de publication posthume,” he used to tell friends. “Don’t pull the Max Brod-Kafka trick on me.” It may have been Foucault who was playing a trick, since Brod is the most famous example of an executor serving posterity by denying the author’s wishes. “Dearest Max,” Kafka wrote when he was dying of TB, “Everything that I leave behind in the way of diaries, manuscripts, letters of my own and from others, sketches, etc … should be burned, completely and unread.” But Brod had already told Kafka he wouldn’t oblige him. Throughout their “unclouded friendship”, Brod “never once threw away the smallest scrap of paper that came from [Kafka], no, not even a postcard”, and he wasn’t about to start now. Without Brod, The Trial, The Castle and Amerika would never have been published.

Facebook Twitter Pinterest Eugene O’Neill and his wife Carlotta Monterey … only through her efforts did many of the playwright’s manuscripts survive. Photograph: Bettmann Archive

Slavish obedience is one route for an executor, defiance for the sake of literature another. When several parties are involved, each jealously possessive of the author, things get trickier. The afterlife of Emily Dickinson was especially vexatious. Her sister, Lavinia (to whom she left her estate), was asked to destroy her private papers, but not her poems, many of which Emily had sewn into booklets and locked in a chest. To get them published, Lavinia first turned to Susan, their brother Austin’s wife, who had been a confidante, adviser and muse to Emily over many years. But Susan dragged her heels on the matter, so Lavinia approached Mabel Loomis Todd, who idolised Emily (despite never having met her) and whom Susan, for understandable reasons, detested – Mabel was Austin’s lover. The edition of the poems that Mabel co-edited with Thomas Higginson helped establish the myth of Emily as a recluse and concealed her close friendship with Susan. The feud – akin to a property dispute (which party had the better claim to own Emily?) – continued through the next generation, with the daughters of Susan and Mabel producing rival collections. In effect, the poems Dickinson left behind were divided between two households. It was 1955 before they were brought together in a single edition.

Similar rivalries afflicted the afterlife of Robert Louis Stevenson, though much of the blame lies with him. He originally intended his biography to be written by his friend WE Henley. Then he added a codicil to his will, requesting that his wife, Fanny, do it instead. Later, he changed his mind again, and asked that the critic Sidney Colvin take over. The work was eventually completed by Graham Balfour, a cousin of Stevenson, whose tactful biography was well received – except by Henley, whose scathing review called the portrait of Stevenson “a barley-sugar effigy of a real man”.

What might be revealed about her husband’s life before they married was a sensitive matter for Fanny Stevenson, as it was for Florence Hardy. It’s a dilemma faced by many biographers as they negotiate between the duty to be candid and the presence of a widow who would prefer certain facts to be played down or withheld. However open-minded, a bereaved partner may take umbrage when a previous partner is given primacy as lover or muse. But if they don’t cooperate, perhaps because private and interview-shy, they will be even more sidelined. Adam Begley’s excellent biography of John Updike acknowledges the help of Updike’s first wife, Mary (“an inspiration to me from the day of our first interview”), but makes no mention of being helped by his second wife, Martha.

Facebook Twitter Pinterest Sylvia Plath and Ted Hughes in New York in 1958. Photograph: Courtesy of The Lilly Library, Indiana University, Bloomington, Indiana.

Where a bereaved spouse is also a literary executor, the problems multiply. When TS Eliot’s second wife, Valerie, forbade Peter Ackroyd to quote from Eliot’s work, “except for the purposes of fair comment in a critical context”, the message was clear: nothing about the man was to be inferred from the poems. In declining to cooperate, Valerie wasn’t just observing her husband’s expressed wish that there be no biography but holding back material for her own project, a multi-volume edition of the letters, still incomplete when she died in 2012. What riled her as much as Ackroyd’s biography was Michael Hastings’s play (and later film) Tom and Viv, and the beliefs to which it gave rise: that Eliot had incarcerated his first wife, Vivienne, in a mental institution; that he’d taken credit for lines in The Waste Land that Vivienne had written; and that he was cold, ruthless and self-absorbed. Perhaps she also minded any suggestion that Vivienne was the woman her husband loved most passionately and “for ever”, when that honour, she felt, rested with her.

However harsh Sylvia Plath's diary was about Ted Hughes, the greater damage was done by him in destroying it

When Jonathan Bate researched his Ted Hughes: The Unauthorised Life, the poet’s widow, Carol, seemed more willing to keep her distance. But when she saw that his work-in-progress wasn’t the biography she hoped for, she and Faber withdrew their cooperation, leaving Bate to publish with HarperCollins instead. Would it have been better for her to stay on board and eliminate the perceived errors and misreadings that so distressed her when the book appeared? Maybe. But managing a literary estate is difficult even for relatively disinterested parties, and if the author is someone you love it’s hard to get things right. Hughes got them wrong when he burned the diary Sylvia Plath had written in her last months: however harsh it was about him (they’d recently separated), the greater damage was done by him in destroying it.

Still, in his mind the journal wasn’t something that anyone (least of all their two children) should read – unlike the poems, which were intended for publication. And for all the criticism of his handling of Plath’s posthumous reputation, he’s not responsible for the recent repackaging of her work. The cover of last year’s UK edition of her letters features a photo of her in a bikini; the 2013 anniversary edition of The Bell Jar depicts a woman checking her makeup; the 2004 edition of Hughes’s selection of her poetry shows Plath bare-shouldered in a swimsuit. There have been protests against this sexualisation of Plath. However appealing to a wider audience, the covers risk trivialising the seriousness of her subject matter and the importance of her work: it’s doubtful Hughes would have endorsed them. The original 1985 edition of his selection from her poems, when he was still alive, had a plain cover.

“I am dead,” Hamlet tells Horatio. “Thou livest. Report me and my cause aright.” For most literary executors doing right by an author is humdrum work: keeping the books in print, looking after royalties, answering letters, selling manuscripts, charging permission fees, and generally ensuring that the authorial brand name goes on even though the author has been discontinued. But it’s not a job to take lightly. The duties are at best thankless (the person who appointed you isn’t around to show gratitude) and at worst it’s an ethical nightmare. Authors are difficult enough to deal with when alive. And things don’t get any easier when they are dead •

• Blake Morrison’s The Executor, a novel with poems, will be published by Chatto on 15 March. To order a copy for £14.44 (RRP £16.99) go to guardianbookshop.com or call 0330 333 6846. Free UK p&p over £10, online orders only. Phone orders min p&p of £1.99.