To mark the 250th anniversary of the U.S. Declaration of Independence, “Revolution” is the timely theme of the Firsts London book fair, opening Thursday in the contemporary art spaces of the Saatchi Gallery.

The fair, running Thursday through Sunday, will feature 100 dealers’ booths on three floors of the neoclassical, early 19th-century building in the upscale Chelsea neighborhood and will take place at a moment of geopolitical convulsion, if not revolution. It also coincides with a profound change in reading habits: Fewer people read for pleasure, and when they do, more often it is on a screen. And yet some physical books are fetching record prices.

Why is that? Clues can be found at Firsts London, regarded as Britain’s pre-eminent fair devoted to collectible books, maps, manuscripts and ephemera. Dealers will be responding to the revolution theme by showing a curated selection of items that document political upheavals over the centuries.

While the organizers — members of the nonprofit Antiquarian Bookseller’s Association and the International League of Antiquarian Booksellers — have been eager to expand the theme to include material that throws light on revolutions in other realms such as science and social attitudes, the momentousness of the Declaration’s anniversary has spurred dealers to bring items with ties to 18th-century America.

The New York-based dealer James Cummins Bookseller, for instance, will be offering a 1775 London printing of Congress’s declaration of the “Causes and Necessity of Taking Up Arms” against the British authorities. Mostly written by John Dickinson and Thomas Jefferson and published just a year before the Declaration of Independence, the document represents a decisive moment in the colonies’ struggle for self-determination. It is priced at $22,500.

“We’re generalists. We’re bringing a bit of everything,” said Jeremy Markowitz, a specialist on American books at Cummins. “But this year, because of the anniversary, we’re bringing Americana that we otherwise wouldn’t have brought.”

The London dealer Shapero Rare Books will be showing a letter written in January 1797 by Thomas Paine, one of the most influential Founding Fathers, to his friend Col. John Fellows who had served with the American militia during the Revolutionary War. The text reiterates the views of Paine’s open letter to George Washington, urging him to retire from the presidency, fearing that the office might become hereditary. With an asking price of 95,000 pounds, or about $130,000. Paine’s letter to Fellows was written just weeks before Washington stood down in March at the end of his second term, a practice later enshrined in the 22nd Amendment limiting presidents to two terms.

Bernard Quaritch, another London bookseller, will be exhibiting a first edition in book form of “The Federalist Papers,” the celebrated collection of essays written in favor of the new Constitution by Alexander Hamilton, James Madison and John Jay from 1787-1788. (These texts are mentioned in Lin-Manuel Miranda’s award-winning musical “Hamilton.”) In its original binding, with the pages uncut and largely unopened, this pioneering work of U.S. political philosophy is priced at £220,000.

The fair, like the United States, has gone through its own process of reinvention. It is the sixth annual edition of Firsts London, but its origins stretch from 1958, when its more traditional forerunner, the London International Antiquarian Book Fair, was founded.

The rebranded Firsts London was initially held at an exhibition space in Battersea Park in 2019, then transferred to the Saatchi in 2021. (There is also Firsts New York and Firsts Hong Kong.) Last year the event attracted an estimated 5,000 visitors over its four days, according to the organizers, and notable sales were made.

“Book fairs are now part of the ‘experience culture.’ In an age where everything is available at a click, fairs have to present themselves in a different way,” the exhibitor Daniel Crouch said.

Crouch will be showing two late-18th-century engraved maps printed on paper of New York by Bernard Ratzer, an engineer commissioned by the British to survey the city and its environs in 1766 and 1767 in case it became a battlefield. Ratzer’s large three-sheet map of the southern end of Manhattan and part of New Jersey and Brooklyn is priced at £240,000; his smaller map of south Manhattan at £25,000. Both date from January 1776, just six months before the Declaration of Independence was adopted in Philadelphia on July 4, 1776.

Other revolutions are also represented. The cover design of Millicent Fawcett ’s classic 1920 Suffragists tract, “The Women’s Victory — and After,” from the collection of the Senate House Library at the University of London, is the poster image for the event and the library is lending the entire pamphlet for display at the fair.

Scientific revolutions are represented by items like a 1976 first edition of Richard Dawkins’s book “The Selfish Gene,” offered at £2,250 by Ashton Rare Books of Market Harborough in Leicestershire, England. Fold the Corner Books in Surrey is offering a handwritten letter by an anonymous British spy describing scenes in Paris in 1791 during the French Revolution, and the dealers at Peter Harrington are bringing a Chinese parade banner from the Cultural Revolution. The banner and the letter are each priced at £750.

While the U.S. document’s anniversary has spurred many exhibitors to show rare 18th-century American items, the organizers stressed the fair’s wider remit.

“We wanted to do something related to our cousins over the water, but something a bit broader than just the American Revolution,” said Tom Lintern-Mole, the chairman of this year’s London fair.

“Revolution is a concept,” he said. “It encompasses everything to do with our world. Printing itself was a revolution. It helps foment revolutions. We like to think that books make history, as well as being artifacts of it.”

In terms of making sales, science fiction and science and fantasy are genres that many traders see as the key growth areas, because of, in great part, recent Hollywood adaptations. “Affluent younger collectors are moving the needle in the market,” said Pom Harrington, owner of Peter Harrington.

Cummins is offering a 1965 first edition of “Dune” for $16,500, while the London-based Foster Books will be asking £22,500 for a 1954-1955 three-volume first edition of “The Lord of the Rings” by J.R.R. Tolkien. It is sumptuously covered in red morocco leather by the binders at Bayntun Riviere.

And with the rise of tech, online sales have increasingly replaced high street transactions, resulting in many rare-book shops closing. Tom W. Ayling, who trades from his home in Oxfordshire and is exhibiting at Firsts London, is one of the most prominent of a cohort of young dealers who sell online and at fairs without the expense of a shop.

“I get almost all my customers through social media,” said Ayling, who has about 298,000 followers on Instagram alone.

Tolkien is a favorite subject for his engaging, regular video posts. Ayling will be bringing a copy of the author’s extremely rare collection of poems, “Songs for the Philologists.” Printed in 1936, only about 15 copies of the collection are known. Ayling is asking £65,000 for this one.

“I put as much content out there as I can to get people interested in book collecting,” Ayling said. “I want to widen the arcane world of book collecting to a mass audience.”

A mass audience collecting — let alone reading — books? That really would be a revolution.