I t’s only a fragment, and it is impossible to make any serious claim for its quality. All that is known of the poem – no printed copy exists – are the following lines, with which it presumably closes:

His quaint-perched aerie on the crags of Time
Where the rude din of this century
Can trouble him no more.

These shards carry a special power for me, as if I first heard them in the nursery. I seem, alas, to have set them on an internal loop to the tune of De Camptown Races , that catchy chronicle of running and gambling. It drives me crazy when I can't make it stop:

Can trouble him no more! Trouble him no more!
His quaint-perched aerie on the crags of Time
Can trouble him no more!

Though the lines were produced by a nine-year-old, no one reading them at the time would have posited exceptional talent, for kids could write like this in the 19th century, if they were bright and had the right schooling. Oscar Wilde turned out reams of such stuff, and not only when he was a schoolboy.

I am overstimulated by such juvenilia, like a bibliographic Lewis Carroll taking snapshots of little persons revealing themselves inappropriately. Is there something creepy about this literary priapism? I am a dealer in rare books, after all, and the blank spaces of this poem are an obsession of mine. I would rather read the unknown rest of it than fill in the gaps of my reading of any major poet, or discover an exciting new one. I am longing to know what opening it might have had, how it developed, and most of all what it looked like.

But what I really want is to own it, this cheaply printed broadside. I’m haunted by its absence, by the faint possibility of its discovery, by the unfinished business of that unpromising text.

It is embarrassing, this greed, without scholarly or aesthetic dimension. To be the only person who owns a copy. To show it off, appear in the papers and on telly clutching it, reading its immature lines with as straight a face as possible. Howard Carter, returned from the young king’s tomb, bearing lost treasure.

Real event
In the opening chapter of A Portrait of the Artist As a Young Man we overhear a violent family altercation over Christmas dinner, and though the book is a novel I have little doubt that such an event actually took place. Parnell had died only a couple of months earlier, and Joyce's father ("Mr Dedalus") was in a rage about the circumstances of his death:

– Sons of bitches! cried Mr Dedalus. When he was down they turned on him to betray him and rend him like rats in a sewer. Low-lived dogs! And they look it! By Christ, they look it!
– They behaved rightly, cried Dante. They obeyed their bishops and their priests. Honour to them!

In the following chapter, away at school at Clongowes Wood College, Stephen recalls the incident, and its effect on him:

He saw himself sitting at his table in Bray the morning after the discussion at the Christmas dinner table, trying to write a poem about Parnell on the back of one of his father’s second moiety notices. But his brain had then refused to grapple with the theme and, desisting, he had covered the page with the names and addresses of certain of his classmates.

That seems right, the child's brain refusing to "grapple" with what is, after all, his father's passion, not his own. Stephen's first poem in A Portrait of the Artist As a Young Man is written years later, in early adolescence, and the haunting villanelle Are You Not Weary of Ardent Ways has nothing of the second-hand about it. It describes the "rude din" of adolescent desire, not of "this century", and there are no metaphorical Eagles quaint-perched in their aeries on the crags of Time.

But it was the nine-year-old Joyce who, in 1891, composed the eulogistic verses that his younger brother Stanislaus later referred to as "the Parnell poem". (Joyce subsequently sanctioned the Latinate title Et Tu, Healy .) Stanislaus, to whose imperfect memory we owe the three lines with which I began, described the poem as "a diatribe against the supposed traitor, Tim Healy, who had ratted at the bidding of the Catholic bishops and become a virulent enemy of Parnell, and so the piece was an echo of those political rancours that formed the theme of my father's nightly, half-drunken rantings".

Stanislaus reports that John Joyce, delighted by his son's production, "had it printed, and distributed the broadsheets to admirers. I have a distinct recollection of my father's bringing home a roll of 30 or 40 of them." He also remembered that, in the (largely destroyed) thousand-page first draft of A Portrait of the Artist As a Young Man , later published under the title Stephen Hero , "my brother referred to the remaining broadsheets, of which the young Stephen Dedalus had been so proud, lying on the floor torn and muddied by the boots of the furniture removers" when the family moved from Blackrock in 1892.

Copy for the pope
Stannie's memory was confirmed by John Joyce himself, who, when asked whether the broadsheet really existed by the bookseller Jake Schwartz, of the Ulysses Bookshop in London, responded: "Remember it? Why shouldn't I remember it? Didn't I pay for the printing of it and didn't I send a copy to the pope?" But repeated inquiries to the Vatican Library by bibliographic busybodies since that time have not unearthed this copy of the poem. Presumably it was thrown out – can they really preserve every insignificant titbit, much less one in praise of an adulterer and sinner, that is sent in for the pope's approval? – but it's a beguiling thought that it might still be there, in some drawer or other.

There is usually a lag between an author’s death and the arrival on the market of significant letters, inscribed books and manuscripts. The mother lode – material held by the author himself, his closest friends and family – often takes decades to emerge, having been passed down the generations until someone decides that the choice between some old letters or manuscripts and a retreat in Provence is a no-brainer. Recent sales of such Joyce material have realised prices sufficient to throw in a modest yacht as well.

After three decades during which almost no significant Joyce manuscript material emerged, all of a sudden there has been such a quantity of it – letters, inscribed books, working notebooks, whole chapters of Ulysses , draft material for Finnegans Wake – that a newcomer might have supposed such sales were common, or that an assiduous forger had secreted himself in a Martello tower to produce it. Between 2004 and 2010 the National Library of Ireland, which previously lacked any significant Joyce manuscripts, spent more than €10 million on manuscript material for both Ulysses and Finnegans Wake . Descendants of Stanislaus Joyce, John Quinn (the New York lawyer and collector who purchased a manuscript version of Ulysses from Joyce in the 1920s) and Joyce's friend and amanuensis Paul Leon have all sold material that alters our understanding of Joyce's achievement. In addition, manuscripts emerging from a Paris bookseller have thrown new light on the history of the composition of both Ulysses and Finnegans Wake . And I am told that TS Eliot's library, which has been visited by only a handful of scholars, contains 14 previously unrecorded letters from Joyce to Eliot.

The more material that is discovered, the more is likely to emerge. There is a magnetic pull when new discoveries are announced and rewarded: it makes people search their attics that little bit more thoroughly, and reconsider whether now might just be the right time to sell. Might the recent glut of Joyce material, and its attendant publicity, not unearth that elusive copy of Et Tu, Healy ? What if it showed up in some disregarded bureau, or interleaved in some old atlas or Dublin directory? Surely if there is one – surely there is one – it must be in Dublin somewhere.

Talking money
In my world, when you're talking ghosts you're talking money. By now you'll be wanting to know how much a copy, if found, would be worth. My business is based on trading in unique material, and I should be able to figure this one out. What of previously lost pieces that have been found? In 2006 Bernard Quaritch Booksellers offered for sale the only known copy of Percy Shelley's anonymous pamphlet the Poetical Essay on the Existing State of Things . Oddly enough, it too was written in support of a beleaguered Irish figure, a journalist called Peter Finnerty, who had been imprisoned for libel for denouncing the foreign secretary, Lord Castlereagh, for abusing Irish prisoners.

The price? Quaritch were asking $1 million, the archetypal roundness of which suggests that they were arbitrarily assigning a value , not attempting to calculate one accurately. If it had been priced at $875,000, it would give one more confidence, carry an authority and suggest some specific computation, however spurious. What about other obscure pieces of juvenilia? There is Evelyn Waugh's The World to Come: A Poem in Three Cantos , printed when he was 13 (£50,000?), and Edith Wharton's Verses , published when she was 16 ($150,000?), but both are known in a few copies, and neither author compares to Joyce in market terms. Perhaps the comparison should be with other Joyce works? A nice example of the 100 signed copies of the first edition of Ulysses is now worth £250,000. Majestic in its Aegean blue, this is the most desirable issue of the most important book of the century. Is Et Tu, Healy worth more than that? It isn't as beautiful, or as important, but it's rarer. It's a ghost.

Who'd buy it? I can think of a couple of private collectors. The National Library of Ireland would surely be interested, the University of Texas might stump up, and sometimes buyers appear at auctions, mysteriously, and then retreat, grasping their treasure, into the obscurity from which they have momentarily emerged. At the Sotheby's auction of material from Stanislaus Joyce's family, someone – not one of the usual Joyce collectors – paid £240,800 for one of the erotic letters that Joyce wrote to his wife, Nora ("my wild-eyed whore"), in 1909, pining with desire during a brief separation. Nobody knew who the buyer was, though rumours suggested Michael Flatley, the Riverdance hoofer, who is known to be building a library. Would he – if it is he – find an Et Tu, Healy even more exciting than an erotic letter?

But until confronted with a copy, he couldn’t really say. No one could, not exactly. Books, like pictures, are valued by both hand and eye: they need to have some kind of visceral appeal, some crackle and pop, which Jeanette Winterson nicely calls the “psychometry of books”. Perhaps the mystique might evaporate when an actual copy emerges and is seen for the trifle that it really is.

Let me ask around: if a copy came up at auction, how much do you predict it would fetch? (Though even this doesn’t necessarily determine how much it is worth, because many items bought at auction are resold quickly and at a profit.) What would Tom Staley make of it? He is director of the Harry Ransom Center at the University of Texas, Austin, the greatest repository of modern literary material in the world, and himself a Joycean. His opinion would partly determine what a copy fetched, even if he wasn’t the buyer.

Asked the question, he is curiously decisive: “a million four,” he predicts (in dollars).

“Would you be a buyer?”

He looks up, twinkling, instantly on the prowl.

“Have you got one?”

I’m flattered that he thinks I might, and sorry to disappoint both of us.

“I’d have to find a donor,” he says, “but I could.”

Peter Selley, of Sotheby's book department in London, who has handled some sensational Joyce manuscript material and letters in the past few years, is less easy about predicting a value. Auctioneers are like that. The comparators, he feels, are the erotic letter and perhaps a spectacular inscribed Ulysses . An estimate of £300,000 to £500,000 perhaps? "Though in an immediate sense it is a far less sexy item than the erotic letter, it does have the obvious huge draw of being absent from every major collection, private and public, plus also tapping into the profound ongoing interest here and in the US in Irish nationalism."

Which is to say, who the hell knows?

There would be a fuss, as the proud owner – me? me! – showed off his treasure, though by a nice irony the text might not be allowed to be printed in its entirety, due to the assiduous protectiveness of the Joyce estate. The old eagle in his eyrie overlooking the world is not, in this instance, the ghost of the late Parnell but Stephen Joyce, the author’s grandson and protector of all things Joycean. So litigious is he that even Christie’s, when they illustrate a Joyce manuscript, have decided to blur the image discreetly, as if it were a model’s pubic hair in an old-fashioned nudie picture. And though Joyce’s previously published work is now out of copyright, it is unclear whether a newly discovered piece would be, or not. After all, it had been published – hadn't it? – so copyright should have lapsed. Can you copyright a ghost?

Never mind. Word would get out – Gekoski has a copy! – and I would have assuaged my interest, filled in the gaps and banished my ghost. The net effect of which, ironically, would be to diminish the interest of the poem, as one could see it finally for what it is, stripped it of its black-tulip numinosity. Bookselling fetishises objects, but usually they are more or less worth the fuss. But Et Tu, Healy ? Fetishisation: 100; Object: 0. This fact, for surely it is that, locates something that lurks disturbingly at the heart of my form of life. There is something dangerous in unrestrained treasure-hunting, a lurking sense of futility, which I, on its occasional outbreaks, find incapacitating.

Ambrose Bierce's Devil's Dictionary defines a ghost as the outward manifestation of an inner fear. This is fair enough: we are frightened of death, and those spooks in sheets are the objective correlative of our terror. As they hover in the night, hooing and wooing, we are reminded of the evanescence of human life, its short span, the long emptiness to come. Et Tu, Healy plays a similar role in my life and is similarly charged: the rattling of its baby chains causes a frisson of anxiety in me, as if my book-dealing life had been dedicated to futile pursuits and meaningless goals. Has there been something unworthy about it, snuffling about like a pig for truffles?

Perhaps if Et Tu, Healy rejoined the world, I might look it in the eye, make an adjustment in our long relations and rid myself of my obsession. I wonder what it would look like. What title might it bear? Who would be named as the author? My bet is on Jas A Joyce, the name under which, some 10 years later, he published his first few articles. James Joyce sounds a little, well, old for a nine-year-old. And surely not Jim Joyce, though that is how he was known in the family.

And what would we be left with? Just a rare piece of paper, a poem written by a little boy and published by a proud father, transformed too quickly from a touching memento to a scrap under the removal men's boots. A lovely thing in its way, with its loss built into its very nature, and, once found, thoroughly forgettable. Just the only known copy of Et Tu, Heal y; nothing haunting about that.

Perhaps then that quaint-perched eyrie on the crags of time will trouble me no more. And if that happens, I will, perversely, rather regret it. Being haunted by a lost scrap and occasionally tormented by a repetitive inner tune is small enough price to pay for the delight of the chase, however futile it occasionally feels. That excitement is strong enough to resist its shadow, and the continued absence of Et Tu, Healy animates and amuses me, when it isn't a source of depression.

I hope it never gets found. I prefer it lost.

Unless, of course, it's me who finds it.

This is an edited extract from Lost, Stolen or Shredded: Stories of Missing Works of Art and Literature , by Rick Gekoski, published by Profile Books