All you need to know about serious watches, from A-Z

Though quartz watches and atomic clocks (like the one that controls your smartphone) will always be more accurate than even the best mechanical watch, the pursuit of high precision in mechanics is still alive today. The fascination behind achieving precision timekeeping in a watch with gears and a mainspring, rather than a battery and an integrated circuit, is a big part of what's kept traditional watchmaking alive in the 21st century.

Abraham-Louis Breguet was one of the most inventive watchmakers who ever lived. Perhaps his most famous invention is a type of watch called a tourbillon. To prevent gravity negatively affecting accuracy, Breguet put the most critical parts of a watch in a tiny, rotating cage (the word "tourbillon" means "whirlwind" in French). The company he founded is still alive today, making tourbillon watches, for a very select clientele.

You can tell a chronograph by the presence of smaller dials within the larger dial, for reading off elapsed time, as well as buttons set into the side of the case for starting, stopping and re-setting the stopwatch function. (Chronographs are often confused by watch newbies with chronometers, watches guaranteed to perform to a certain accuracy standard.) Chronographs are often associated with motorsports and aviation. One famous model, the Omega Speedmaster, was standard issue for Apollo astronauts and is still used in manned space flight today.

If there's one type of watch that competes with the chronograph for popularity, it's the dive watch. Watches designed for diving first appeared in the late 1930s, from naval suppliers like the Italian firm Panerai. However, the modern dive watch dates back to the mid-1950s, when Blancpain's 50 Fathoms and Rolex's Submariner both appeared. These watches established the design of modern dive watches: significant water resistance; a screwed-down winding and setting crown; instant legibility and a rotating bezel (the grooved ring which holds the watch face in place) for timing dive times and decompression stops.

Today the term "dive watch" is regulated by an international standard that requires those features, as well as a minimum of 100 meters' (328 feet) water resistance. But the appeal of the dive watch is so wide that most are worn by owners who'll never dive at all.

Imagine a pendulum swinging back and forth. If you have a mechanism to keep the pendulum swinging and additional parts for counting the swings, you have a clock. In a mechanical watch, a mainspring keeps the watch going (that's right, a mechanical watch is a wind-up toy) and instead of a pendulum, a balance-wheel swinging on hair-fine steel pivots oscillates back and forth, but the principle is the same: there's a mechanism for keeping it swinging, and counting the swings. This is the escapement. Fun fact: the lever escapement, used in virtually all modern watches, was invented in England in 1755.

Recently there's been a huge revival of interest in extra-flat watches. Making this type of watch presents big challenges. Extreme care and precision are necessary to achieve accuracy and reliability. Traditional leaders in the field, like Jaeger-LeCoultre, Vacheron Constantin, and Piaget, vie to create ultra-elegant ultra-flat watches, but relative newcomers like Bulgari make excellent examples as well.

Think Switzerland is the only country making killer timepieces? Think again. Seiko is often thought of as a maker of entry-level quartz watches and tough but affordable mechanicals, but they also make Grand Seiko, a range of watches with quality fit, finish, and precision. For many years, Grand Seikos were made in small numbers and only available in Japan but today they are increasingly sold internationally. They offer a level of quality that would cost significantly more from a Swiss manufacturer, which is why they've been a watch insider's cult favorite for many years.

Though their watch straps are legendary among aficionados (the high-end brand Parmigiani Fleurier is known to source most of their straps from Hermès), they also make a wide range of fashion-forward wristwatches, as well as unusual, complicated mechanical watches and even pocket watches, often decorated with beautiful engraving and enameling.

The International Watch Company of Schaffhaussen, Switzerland, is an anomaly. The Swiss firm was founded in the late 19th century by an American Civil War veteran by the name of Florentine Ariosto Jones, who was one of the first to attempt to introduce American manufacturing methods to the Swiss watch industry. Today, IWC is perhaps best known for its many high-profile film tie-ins, but behind that is a company that's made some of the most famous "tool" watches of all time. This includes their Aquatimer dive watches and the legendary "Mark" series of antimagnetic pilot's watches, which were widely used by both military and civilian flyers post-World War II, and are still in production today.

Jaquet Droz is named for an 18th-century watchmaker who was also famous for making automatons, clockwork robots that could perform tasks in a human-like fashion. Today the company keeps this tradition alive with its own automaton wristwatches. At the top of the heap: the "Charming Bird" wristwatch in which a tiny robot bird spins and chirps a song, thanks to a built-in mechanical pipe organ.

If you don't know what a key-wound watch is, don't worry -- they've been gradually falling out of fashion since the mid-1800s. But once upon a time, all watches were wound by sticking a key into the back and turning it. It was troublesome, and often led to dirt inside the watch where it shouldn't be. (In a Sherlock Holmes story, the great detective deduces that a man was a drunk from the many scratches around the hole for the winding key on his pocket watch.) Nowadays, you can wind and set a watch just by turning the crown, or pulling the crown out to set the time -- the first modern version of this system was developed by the high-end watchmaking firm of Patek Philippe in 1845. Today such mechanisms are called "keyless works."

The first clocks and watches with glowing hands used an incredibly dangerous radium-based paint that was bright, beautiful and, unfortunately, highly radioactive. Many of the workers who applied radium paint succumbed to cancers. Nowadays, most watches with glow-in-the-dark hands use a material called Luminova. It may not glow spontaneously like radium (it needs to be "charged" by exposure to light), but it is completely safe.

This was particularly a problem for anyone working around electrical equipment -- pilots, for instance, since airplane engines generate strong fields. Rolex developed its magnetism-resistant Milgauss in the 1950s for industrial and scientific engineers and technicians. Today, Omega makes a watch -- the Seamaster Aqua Terra -- that is so immune to magnetism that it won't even be thrown off by the powerful magnetic field of an MRI machine.

To make watches more reliable, accurate, and durable, modern watchmaking uses manufacturing methods capable of producing micron-level precision, from computer-guided milling machines (standard in watchmaking today) to nanotech manufacturing techniques like silicon fabrication and even more exotic methods like the micro-lithography technique known as LIGA. A watchmaker from 100 years ago would understand how a watch of today works, but the processes would make his jaw drop.

Over the course of its history, Omega has been an industry leader in just about every way that matters. They've developed everything from wristwatches and marine chronometers, to pioneering watches for deep diving and ocean exploration. Omega timepieces have been just about everywhere -- including space. The Omega Speedmaster's most famous moment as "the Moonwatch" came when it was used by the Apollo 13 crew to time critical firing of their crippled spaceship's rocket to ensure a safe reentry. (Cabin instruments were shut down to save precious battery power.)

Founded in 1851, the name has, since its inception, been synonymous with the very highest level of finesse. Patek Philippe's watches are beautifully crafted, often mechanically innovative and, just as importantly, they're some of the most collectible and valuable watches on the planet. Want proof? Patek Philippe watches routinely break and set records. The highest price ever paid at auction was by an anonymous collector who, in 2015, paid $24.4 million for an ultra-complex pocket watch made in the 1930s for American banker Henry Graves.

Though they're commonplace nowadays, quartz watches were not only the very hottest thing in watchmaking, but also coveted luxury items when they were first released. The very first quartz watch ever was Seiko's Astron, which went on sale in Japan on Christmas, 1969, and cost as much as a new car. Mass production and lowered manufacturing costs meant that eventually anyone could have chronometer accuracy on their wrist. Many thought the so-called "Quartz Crisis" would kill off mechanical watches completely, but today, fine mechanical and durable, dependable watches, like Casio's famous G-Shock, happily coexist in the marketplace.

People who've never heard of any other watch company have heard of Rolex. And for good reason: no company has been so successful at insinuating itself into the public mind as this Swiss watch brand. Rolexes have been seen on innumerable wrists in the movies, starting with Sean Connery's Bond. The classic novice's goof is to think of Rolex as all show and no go, but real horological insiders know that Rolex's movements are some of the most accurate, robust and reliable on the planet.

Lighter than steel and, critically, non-magnetic, silicon has a huge advantage over traditional alloys. Silicon is part of what's behind the resistance to magnetism of Omega watches, and you might be surprised to hear that Patek Philippe, a company that's identified with doing things the old-fashioned way, has embraced silicon technology for moving parts in many of its watches as well.

Timex is an older company than most might imagine. It was originally founded in 1854 as the Waterbury Watch Company and, in one form or another, has been around ever since. Timex was one of the first brands to make inexpensive watches accessible to the masses. The brand continues that tradition today. Their biggest hit in advertising was a series of TV ads in which they would do spectacular torture tests -- involving things like jackhammers, paint mixers, and outboard motors -- and then show the watch running unscathed, with the world-famous tagline: "Takes a licking and keeps on ticking."

These watches have an extra hour hand that shows the time in a different time zone. Typically, the main hour hand can be reset, independently of the other hands, in one-hour increments as you cross time zones while traveling, so it always shows the correct local time. A second hour hand, pegged to a 24-hour scale, shows home time, so at a glance you can see the time where you are, and the time at home. The classic model is the Rolex GMT Master, originally produced by the company for Pan Am pilots to help fight jet lag.

Vintage watch collectors are incredibly varied in terms of what catches their eye, and focuses can be narrow and intense. Some people, for instance, collect only vintage Rolex Submariners with rare or unusual dials. You need deep pockets if you're one of them: vintage Rolex, like vintage Patek, have skyrocketed in price in the last decade, with some vintage Omega models, like the Speedmaster, not far behind. But buyer beware: the incredible prices some vintage watches routinely hit at auction have made creating fakes a lucrative business.

A ring on the dial, showing the names of major cities in each time zone, has inside it a 24-hour disc that rotates once a day. Whichever hour is lined up with a given city is the current time in that city. A practical and beautiful complication, its only drawbacks are that it can't compensate for Daylight Savings time, and that some time zones are not a whole hour apart. However, some modern manufacturers have created world time watches that show the time even in those oddball time zones -- a beautiful, if pricey, example is the Traditionnelle World Time wristwatch from Vacheron Constantin.

The inventor of G-Shock is Casio engineer Kikuo Ibe, whose beloved mechanical watch broke accidentally. He then vowed to make a watch that was unbreakable. The first G-Shocks came out in the mid-1980s and they were tough alright. Ibe famously tested prototypes by throwing them out of the fourth-floor men's room window at Casio's research laboratory, into the parking lot below.

The challenge is that there aren't a whole number of days in a year. Instead, it's about 365 and a quarter days to make one trip around the Sun -- which is why months are different lengths, and why February has a day added once every four years to keep the calendar in sync with the seasons. The watchmaker's solution is a type of watch called a perpetual calendar. Such watches contain a tiny mechanical computer that automatically detects the correct length of each month, and always displays the correct date -- even at the end of February in a leap year. These watches are traditionally very expensive, but a major trend nowadays is creating more affordable perpetual calendar watches, like the Montblanc Meisterstück Heritage Perpetual Calendar, which starts at less than $10,000.

Zirconium dioxide, also called just plain zirconia, is a ceramic. Yes, so is your grandmother's Wedgewood china, but there the resemblance ends. Zirconium dioxide is a tough, highly scratch-resistant material that's part of a big trend in the last decade of watchmaking to replace steel or aluminum case parts with scratchproof ceramics. Rolex and Omega, as well as a huge range of other firms like Blancpain and Rado, use the material for bezels and even entire cases, and you'll find ceramics commonly used in modern watch movements as well, where they are used for ball bearings in the automatic winding mechanism.