Dennis Smith is a retired New York City firefighter and a writer.

Simon Winchester is an Oxford-trained geologist and a writer.

Even if you didn't know these differences in the men's backgrounds, you'd readily guess them from the widely divergent themes explored in the authors' new books on the same subject: the 1906 earthquake and subsequent fire that all but destroyed San Francisco.

Smith employs historical records to uncover a dismaying story about how negligence, corruption, poor planning, political maneuvering, bad luck and ill-thought-out policies led to the extensive destruction of the city by fire, much of it preventable.

He makes clear how spin control played a role in the event's popular name: It's almost universally referred to as the San Francisco Fire when the triggering event was an earthquake. This is because it was vital to the city's business interests that the new buildings be insurable; fire was insurable, earthquake damage was not, Smith said. (The quake, incidentally, estimated to have been of a 7.8 magnitude on the Richter scale, still ranks as the largest recorded in the continental U.S.)

In sharp contrast, Winchester's book roams from tangent to ultimately relevant tangent: Old Geology, New Geology, plate tectonics, the Gaia Hypothesis, Einstein's Theory of Relativity. We don't even get to San Francisco in any significant way until page 201. The work is something of a literary dalliance, built on the thin conceit of a cross-country trek by car from Winchester's home in Boston to San Francisco. He would drive virtually all the way across the North American Plate, the plate whose restless shifting caused the 1906 earthquake, and along the way, he would ponder "the undersurface of North America."

This trip, like so much else, frequently gets lost in the telling. Sometimes it feels as though in his relentless effort to place the San Francisco earthquake in context, Winchester is having a little fun with the reader — purposely trying to see how far he can wander from the point without losing it entirely. It's a measure of his skill that he does always remember to weave the new thread into the fabric of the book.

Both men are well-known craftsmen in their fields. Smith's "Report From Engine Co. 82" (1972) is a classic and his "Report From Ground Zero" is considered to be one of the best to come out of the terrorist attacks on the World Trade Center. Winchester's "Krakatoa" and "The Professor and the Madman" were both New York Times best-sellers, widely reviewed and praised.

Winchester is without question the more graceful and challenging writer. Smith's writing is straightforward and a great deal more concerned with the human; he makes use of vignettes to move the action forward and takes time to tell us what happened to all the key figures afterward.

In Honolulu recently for a meeting of the International Association of Fire Chiefs, Smith (now an independent consultant, he serves on an IAFC committee that's investigating causes of firefighter deaths) said the biggest surprise for him in researching the book was in discovering a hero. This was a man after his own heart — professional, knowledgeable, courageous and concerned only with what matters, not with political fallout.

That hero was Lt. Frederick "Frisky" N. Freeman, a Navy man whose quick action would save San Francisco's wharves and railroad sheds. "He understood how to fight a fire intelligently. ... He was an engineer with vast experience. He read a lot. He subscribed to Water Engineering magazine, the predecessor to Firefighter magazine. He would have known about the Great Baltimore Fire of 1904. ... An amazing man," Smith recalled.

It was also sad for Smith to note that the story might have been much different had not another skilled man, San Francisco Fire Chief Dan Sullivan, been fatally injured in the first few minutes after the quake. His hospitalization and death, as well as the absence of a local Army commander and other key figures, left a power vacuum that contributed to the involvement of less desirable political and military figures in the management of the crisis.

Neither Smith nor Winchester is merely writing history (or geology) here. Both are communicating not-so-subtle warnings.

This could happen again — and will, they are saying.

"It is," writes Winchester in his final chapter, "only by the planet's consent ... that all towns and all cities ... survive for as long as they do. ... This consent is a privilege, and one that may be snatched away suddenly, and without any warning at all."

And, Smith cautions, we should not comfort ourselves that, with all the advances in technology and fire science since 1906 such devastation could not be repeated. He's thinking not so much of 9/11 as of Hurricane Katrina in New Orleans, which uncovered many of the shortcomings that exist in cities around the world: short-sighted budgeting that cuts money for disaster preparedness in favor of short-term needs, an unclear chain of command and, ironically, a certain undaunted optimism on the part of Americans that causes them to be willing to live in the sure path of some future hurricane (or earthquake or tsunami) and believe it just won't happen.

Investing in emergency preparedness, Smith said, is insurance.