In a tone-setting keynote delivered this morning at the London Book Fair’s Quantum conference, Penguin Random House U.K. chair, Gail Rebuck told attendees that for all the “curious incidents” she’s witnessed over her publishing career—from her days binding and setting hot type at the London College of Printing, to the emergence of e-readers—books remain the “DNA of our civilization."

In her 20-minute talk, Rebuck acknowledged a series of seismic shifts in the book business over the last two decades, and both the potential—and the pitfalls—of technology for publishers and authors.

“Today our job as publishers is made easier, and infinitely more sophisticated, by terabytes of digital research and sophisticated insight tools that enable us to segment audiences by their passions and their literary tastes, to reach readers with the individuality of an email message, to constantly refresh and repackage the way books and backlists are managed and marketed,” Rebuck said. But, she also noted a “concerning decline in authors’ revenues,” adding that only one in 10 writers today live on their writing income alone, and that half of all self-published authors earn less than $500 a year.

She went on to cite the “complexity of the modern world” for the pressure on today’s publishers and authors: squeezed margins across the whole supply chain, the lack of diversity in e-book distribution, price deflation, and competition from other media for readers’ time.

“The technology that has made it easier than ever to tell a story and get it out to the world cuts two ways,” she noted. “It’s made it possible for a handful of authors to hit a global jackpot of unprecedented, Himalayan, proportions, while at the same time making it so much tougher for many authors to be seen or heard in the vast sea of information in which we now live.”

Rebuck also cautioned publishers against framing digital and physical as “enemies,” insisting that “what matters is that readers are discovering and buying books, whatever the form of delivery.”

Rebuck’s speech echoed some of the observations of bestselling British author Philip Pullman, who gave the afternoon keynote at the 31st International Publishers Congress Sunday.

In his talk, Pullman, like Rebuck, stressed that the central role of storytellers remains, while acknowledging “four revolutions” over the course of history: the emergence of the oral tradition; the transition from an oral tradition to written language; the advent of movable type and the codex, and finally, digital.

In each case, Pullman noted, new ways of doing things did not entirely replace to the old ways, and suggested the e-reading devices like the Kindle may in fact be reminding readers today of the elegance and functionality of the codex.

But Pullman also cautioned against the developing digital world, where public libraries are being cut, and books are considered cheap. “Things from the third revolution are still needed in the fourth,” he said.

“If I was a publisher today, I would ask most urgently what it is that makes me necessary to writer and reader, to storyteller and audience," he said, observing that publishers need to look carefully at what they bring to the publishing process in order to "survive and prosper" into the fifth revolution. "Because," he concluded, "there will be a fifth revolution."