A valuable life lesson: Don’t get too near an erupting volcano. Look what happened to old Pliny, the ancient Roman naturalist and naval commander. When Mount Vesuvius, east of Naples, blew its top in 79 C.E.—famously burying the towns of Pompeii and Herculaneum—Pliny (rhymes with “tinny”) borrowed a ship from the Roman imperial fleet and sailed across the Bay of Naples to have a look. Lethal fumes from the volcano killed him, by some accounts saving him from an even uglier death by incineration.

It makes for one of those classic cautionary tales in the curiosity-killed-the-cat vein. But there’s more to it than all that. Pliny’s curiosity is the very stuff of scientific inquiry, which sometimes entails danger. That’s one thread that emerges in Daisy Dunn’s new book, The Shadow of Vesuvius: A Life of Pliny (Liveright, Dec. 10), which in turn reflects long-held curiosity on the part of its author, an English classicist and art historian. “When I was a child,” Dunn tells Kirkus Reviews by telephone from her home in Surrey, “I read a story about this brave man who set out to look at Vesuvius as it exploded. He was incredibly courageous and incredibly curious—that’s the inspiring story I took away.”

Then, Dunn recalls, she sat down to read Pliny’s multivolume Natural History, the first encyclopedia known to us. Only a small number of the 160 volumes survive today. Still, says Dunn, “It took a long time to get through. What I was really surprised to find was that he had a long section on volcanoes in the book already, and he didn’t mention Vesuvius, which had been dormant for a long time—so long that it made me think that people of Pliny’s time didn’t know that it was a volcano, too, or thought it was a volcano that would never explode again. That all changed the reasons, I thought, for his going to Vesuvius when it did explode. He wanted to see what that strange cloud rising up across the water was. What I ended with is not so much a tale of courage, as I had thought before, but instead one of true curiosity.”

Pliny’s curiosity had an overarching purpose: As an encyclopedist, he wanted to get down all he could of human knowledge while he could do so, knowing that such knowledge had a way of disappearing in a time of burned libraries and vanquished civilizations. Vesuvius hadn’t exploded for 700 years, we know from modern volcanological reports, and he was duty-bound to report on it when he saw it blow. “Vesuvius was green and beautiful, covered with vineyards, and the people who lived there were mesmerized by the mountain,” Dunn says. That complacency explains why so many Romans ignored its rumblings and died in ashes and fire 20-odd centuries ago. Most were anonymous victims. Pliny is one of the few felled by the volcano whose name we know.

Complicating Dunn’s story is the fact that there were two Plinys, known to us today as “the Elder” and “the Younger.” For centuries, only the first was well known, for his encyclopedia—which, Dunn allows, was often “catastrophically wrong”—remained well read until recent times.

The younger Pliny, his nephew, was also a writer, a student of Quintilian’s and friend of the historian Tacitus, but, as Dunn says, “he lived in his uncle’s shadow.” The younger Pliny entered government service, ending up as the governor of a province on the Black Sea, and managed to avoid getting caught up in the sometimes-lethal machinations of the emperor Domitian, whom Pliny, Dunn says, “paints as a monster.” Modern historians tend to cut Domitian a little more slack, considering him a capable if authoritarian leader of the rapidly growing Roman Empire (which didn’t save him from being assassinated by his bodyguards).

Dunn’s portrait of the two Plinys brings those once-well-known figures back to center stage in Roman history. She finds both figures to be curiously modern. “They wrote about sustainable agriculture, organic wines, respecting nature,” she points out. “Pliny the Elder even worried that by digging mines, we were damaging the planet irreparably.” If the planet responded by setting off a few volcanic explosions in turn, that was only natural—and something worth looking into.

Gregory McNamee is a contributing editor.