Bending over a vitrine at a rare-book fair, a father and son asked me to name the most exciting discovery I’d ever made inside a book.

‘What sort of thing?’ I asked, thinking of pressed flowers, locks of hair, tram tickets.

‘Have you ever found a treasure map?’

It surprised me that it was the father who suggested this, but only a little. He was giving expression to the atavistic idea that books contain arcane secrets (which, of course, they do), mixed with the magical thinking that wishes away the chore of reading them. I wondered how to explain that the most enthralling discoveries I’ve made in old books are marks left by previous readers.

This year sees the four-hundredth anniversary of the publication of the first collected edition of Shakespeare’s plays, the fabled First Folio of 1623, produced seven years after his death. This thick volume ensured the survival of eighteen of his plays, nearly half the Shakespearean canon. The folio was reprinted three times within the century, in 1632, 1663 and 1685, with minimal changes. The single substantial innovation was the inclusion in the Third Folio of seven further plays, but of these only Pericles is now admitted as being, in part, by Shakespeare.

Shakespeare would surely have been astonished at this. His biggest lifetime publishing success was his erotically charged poem Venus and Adonis. Those few of his plays printed while he was alive, often imperfect texts cobbled together from the memories of actors, appeared in cheap quarto editions intended for theatregoers. The posthumously published folio editions, by contrast, were prestige objects produced for private libraries.

The continuity of text and format across all four folios glosses over a massive mid-century disruption: the destruction of the theatre as Shakespeare had known it. During the Civil War and Interregnum, all London theatres were closed and theatrical performances banned. Shakespeare’s company, the King’s Men, was dispersed in 1642. The Globe and Blackfriars Theatre were torn down in 1644 and 1655 respectively.

Only three plays by Shakespeare were published during the Interregnum, in defiance of the prevailing mood. The Merchant of Venice appeared in 1652 and King Lear in the same year that Blackfriars Theatre was demolished. Last year, at the London Antiquarian Book Fair, we found a copy of the third: The tragœdy of Othello, The Moore of Venice. As it hath beene divers times Acted at the Globe, and at the Black-Friers, by his Majesties Servants. It was published in 1655 by William Leake, whose father had published several editions of Venus and Adonis.

Texts like these usually survive in volumes of plays bundled together (though valuable Shakespeare titles were sometimes extracted and rebound individually, shorn of context). But this copy was bound in a volume of miscellaneous pamphlets, mostly from the 18th century, passed down through several generations. Two things about the Othello quarto struck me. First, the pages had been annotated, comparing the text with that of the first quarto edition of Othello of 1622 rather than with the folio text published the following year, an unusual level of editorial sophistication.

Second, and more thrillingly, on a flimsy piece of paper facing the title page was a manuscript cast list, showing the great Restoration actor-manager Thomas Betterton appearing in the title role. By triangulating the careers of all the cast members, I was able to date the list to between 1695 and 1698. Most likely, it came from a production staged at the new theatre at Lincoln’s Inn Fields. This was not a copy of material printed elsewhere. All editions of Othello published between 1681 and 1705 reprint an old cast list for the production put on by Thomas Killigrew’s King’s Company, with Charles Hart (who died in 1683) in the lead. The handwritten list scribbled at the start of our edition seems to a portrait taken from life.

And what a portrait. The most visible innovation in Restoration theatre was that female actors were now free to play female characters. Desdemona in this production was played by Anne Bracegirdle, one of the first leading ladies of the English stage, fostered from infancy by Betterton and his wife. Acting opposite her as Emilia was Frances Maria Knight, later of the company of the Theatre Royal, Drury Lane. A couple of years earlier, both women had been involved in a notorious trial heard before the House of Lords concerning the stabbing of the actor William Mountfort. The murderer’s motive, in a startling echo of the plot of Othello, was jealousy of the actor, whom he had imagined Anne Bracegirdle to be in love with.

This cast list nudges us towards a new era of Shakespearean publication. After the Fourth Folio, in 1685, the next collected edition was that produced by Nicholas Rowe in 1709. This appeared in a more convenient and portable format, consisting of six octavo volumes, with a single-column page setting and a generous font for easier reading. An experienced playwright, Rowe supplied sensible additional scene settings and directions. He also wrote the prefatory biography of Shakespeare, another new feature, for the ‘most considerable part’ of which the convivial editor owed a ‘particular obligation’ to his friend Thomas Betterton. Each play was separated into the acts and scenes familiar to us today and illustrated with an engraving of a contemporary stage production. The frontispiece for Hamlet shows Betterton in the title role.

Rowe was not an interventionist editor and mostly reproduced the text of the last folio, which, as a fourth-generation copy, had accumulated errors of transmission. In two instances, however, he made changes. His text of Hamlet, like his biography of Shakespeare, is indebted to Betterton, who acted in Sir William Davenant’s 1661 version. The only other play Rowe altered is Othello, adopting textual variants from the first quarto edition of 1622 – the edition with which our copy is also contrasted.

My treasure map takes me thus far and no further. I cannot put Rowe in the same room as this copy. While noting that Rowe’s first six plays all starred Thomas Betterton and Anne Bracegirdle, I cannot identify the cast list as being in his hand. Nor can I link Rowe, who had no descendants, with the later owners of the volume.

Amid the glut of Shakespeare-themed offerings we will no doubt see from rare-book sellers in 2023, this unshowy quarto Othello may prove one of the most intriguing. After all, a treasure map does not itself contain the spoils but points the way to riches still tantalisingly out of reach.