The story began with a warning: “I have attempted to compose a book that shall neither be too abstruse for the gay, nor too amusive for the learned,” the author wrote . “Possibly in attempting to find a middle way which would accommodate philosophy of every class, I have chosen one that will not be agreeable to any.”

So started Conversations on the Plurality of Worlds , a dramatic work by French philosopher Bernard le Bovier de Fontenelle. In the best-seller, published in 1686—one year before Newton’s groundbreaking Principia —Fontenelle introduced the lay public to Cartesian philosophy and the early science of the natural world. The story features two speakers, a man and a woman, discussing the features of our solar system and the use of scientific inquiry to illuminate the laws of nature. The writing proved so popular and accessible that Fontenelle’s work went through six editions during his life and was reprinted another six times by 1825.

Not only did the book pave the way for other natural philosophers ( the word “scientist” wasn’t coined until 1834 ), it inspired an entirely new genre of writing: popular science. And with scientific subjects suddenly in vogue, more and more European citizens were swept up by the Enlightenment, that murkily defined period in the 18th-century that ushered in a new way of thinking about and exploring the world.

To understand just how radical Fontenelle’s popularity was, consider earlier natural philosophers like Copernicus (who theorized that the Earth revolves around the sun) or Johannes Kepler (who discovered the laws of planetary motion).

“[Their] books come out in editions of 500 copies and maybe 50 people read and understand them,” says Michael Lynn , a professor of history at Purdue University Northwest. “Newton comes along and writes his book, and maybe 100 people understand it, but now people are more invested in trying to figure out what to do with it.”

Fontenelle proved there was an audience for accessible science in local vernaculars; now other writers merely needed to follow his example. In the wake of Fontenelle’s work came dozens of new books. Newtonianism for Ladies , by Francesco Algarotti, made the famed scientist’s complicated mathematic principles much clearer. The Encyclopedia of Diderot and d’Alembert discussed everything from algebra to surgery. Literacy was booming across Europe, as were printing presses. Suddenly readers could find scientific research discussed not only in books, but also in newspapers and street performances where showmen demonstrated the properties of electricity.

Accumulating knowledge about the natural sciences also gave one a certain cachet, Flynn says. Like watching Bill Nye or reading the works of Carl Sagan today, knowing what was happening in the world of science was thought to make a person more cultured and capable of rational decision-making.

Given Fontenelle’s success translating science for the general public, some researchers suggested that French was the necessary vernacular for participating in the sweeping transformations of the time. As Marc Fumaroli argues in When the World Spoke French , a large portion of the international community spoke or read French in the 1700s. Researchers Johanthan Topham and Simon Burrows even created a database for 18th-century Swiss publisher Société Typographique de Neuchatel that reveals tens of thousands of popular science books written in French that were purchased across Europe—everywhere from the United Kingdom to Russia.

“I think it’s arguable that the lingua franca of the Enlightenment is French,” Flynn says. “But there are whole books written about how the Enlightenment is not just French. Each country has its own style. There’s an Italian Enlightenment, a North and South German Enlightenment.”

As science historian Lindy Orthia of Australian National University points out, the diffusion of science wasn’t just about language—it also depended on each country’s social circumstances. “In the late 18th and early 19th centuries, Britain and France were really the stand-out nations in terms of mass movements in popular science, particularly in Paris and London,” Orthia says by email. “But if we compare France to other places in the world, perhaps what stands out is the importance of urbanization and centralization, as well as the growing institutionalization of science.”

In other words, would-be pop-sci writers needed support from groups like the Royal Society of London or the Académie des Sciences in Paris, as well as interest from the public. For French philosophes , both came in large supply. In addition to Fontenelle, other science writers of the Enlightenment era include Émilie du Châtelet (who translated Newton’s work into French), chemist Antoine-Laurent Lavoisier (who created a system to identify chemicals) and Nicolas de Condorcet (who argued for the use of scientific reasoning in democratic governance).

But perhaps above all others was François-Marie Arouet, better known as Voltaire. The prolific writer penned hundreds of essays and stories, his overall works spanning more than 70 volumes, including essays on Newton’s research . (Voltaire even built his own lab but didn’t do much experimenting.) “A lot of the popular science stuff is more specialized,” Flynn says, meaning writers would choose to focus on either natural history or chemistry, physics or botany. “Voltaire is a bad example because he was so able to write in any format. He’s exceptional. He writes history, science, short stories, poems, plays, letters, philosophical criticism. Few people could transcend literary genres quite like Voltaire.”

The specialization that Voltaire eschewed helped redirect the course of future scientific studies—and in some ways spelled the demise of science by and for the masses. Because the importance of scientific research had been so effectively communicated to political leaders and the wealthy upper-class, more support was thrown behind leading scientific institutions. Individuals were directed to take more distinct research paths in a professional setting, a shift away from the ad-hoc work previously pursued by those with the right combination of curiosity and leisure time.

“That professionalization process had the effect of setting up boundaries between ‘scientists’ and anyone else who might be interested in science, so it led to the exclusion of a whole bunch of people from formal scientific activity,” Orthia said. “Arguably, popular science created its own demise by making science too popular and too successful.”

The same principle governs scientific communication today. You may watch “Planet Earth” or read books by Richard Dawkins, but that doesn’t make you a biologist. And for that, Orthia says, we likely have the Enlightenment to thank.