If the Italian military had not switched sides to fight alongside the Allies in September 1943, watch collectors would probably not be so passionate about Officine Panerai. They would still be impressive timepieces, beautifully crafted and distinctively styled, but in the service of Fascism alone precision is harder to love. Originally made for Mussolini's commandos sailing mini-submarines into Mediterranean harbors, Panerais are now found strapped to wrists of men struck by the watch's distinctive sapphire crystal face, Arabic numerals, and half-moon crown guard.

These watches are owned and loved by a select group of purists around the world, making it hard to classify the atypical Panerai fanatic. To them, the watch is both an instrument for measuring time and a witness to heroism past. The proud faces often are an inch-and-a-half wide, so the watches are not to be worn lightly—literally or figuratively. Collectors of these watches, known as Paneristi, range from the mildly detail-conscious to the obsessive, versed in every aspect of mechanics and meaning. No one watch is that different from the next in looks or performance. But because they are totems of masculinity and signifiers of taste and status, detail is everything. The Radiomir models, for instance, take their name from a special blend, now discontinued, of gamma-ray-emitting radioactive materials. The numerals once glowed in the ocean's darkest depths.

For some years now in Europe, Panerai watches have been part of the uniform for the man set on a precision course for the blonde at the bar of the Cipriani. In America, thanks to Panerai-wearing celebrities like Brad Pitt, professional athletes (the entire defensive lineup of the Green Bay Packers), and politicians, including Bill Clinton and Arnold Schwarzenegger, the popularity of Panerai is rapidly growing. Unlike many types of dress watches that need to be in perfect condition to be fully appreciated, Panerai watches look best when they have been scuffed by life.

The modern Panerai man may not spend much time underwater, but it pays to be prepared, and the watch has a good story to tell. "The luxury of Panerai grew out of its heritage and the purposefulness of each detail," explains designer Ralph Lauren, owner of a highly prized Radiomir model made for the Egyptian military. "These watches were not about the latest fashion—they were designed to work in specific conditions. Their form and beauty were secondary to their function; they're rugged, utilitarian, and handsome."