A. Lange & Söhne is a trademark of premier German watchmaking company Lange Uhren GmbH. Its watches rank among the finest in the world and sell in the same general price range as watches made by such top-tier Swiss firms as Patek Philippe and Vacheron Constantin.

Lange was founded in 1845 by Ferdinand Adolph Lange in the little town of Glashütte, near Dresden in the state of Saxony. In 1948, the post-war Soviet administration expropriated the company's property, and the Lange brand ceased to exist. But in 1990, after the collapse of the East German communist government, Adolph Lange's great-grandson, Walter Lange, restored the company with help from a family of Swiss watch manufacturers including IWC. Now A. Lange & Söhne, like IWC, belongs to the Richemont group of companies.

All Lange watches are mechanical rather than quartz-driven, and, with the exception of a few special edition watches, all Lange cases are made of precious metals (gold or platinum) rather than steel. All Lange movements are developed, made, and assembled in-house. Lange is also a pioneer in watchmaking technology. For example, it developed a rare "double split chronograph" that enables a wearer to time two events for up to 30 minutes. The company also developed an innovative fusee winding system used in certain models.

More recently, on March 15, 2007, the company unveiled the culmination of a multi-year effort to produce the first wearable mechanical watch with a 31-day power reserve: that is, a watch that need be wound only once per month (with a special key). To guarantee the power reserve for a month, the brand's watchmakers used two stacked mainspring barrels that store the required energy. The big-sized barrels made it necessary to apply two mainsprings that are 5-10 times longer than those found in other wristwatch movements. At this point, Lange specialists faced a serious problem - a common winding crown train was not suitable for winding such strong mainsprings. To solve that problem, the watchmakers used the 'key technology' of A. Lange & Sohne pocket watches. Some Lange admirers lauded these technological achievements, while others expressed skepticism that there would be a significant market for this very large (46 mm wide by 16 mm deep) and expensive (almost $180,000) platinum-cased watch.

Lange watches tend to have a highly distinctive appearance. For example, the iconic 38.5 mm "Lange 1" model features an asymmetric layout with no overlap among its key components: a dial containing the hour and minute hands, a smaller dial containing the second hand, a double window containing oversized digits for the date, and an "ab auf" meter registering the degree of wind left in the watch. Lange's watches are often described as more "austere" or "Teutonic" in appearance than comparable watches produced by Patek Philippe and similar Swiss firms. Finally, Lange watches typically feature a "display back" -- a transparent surface on the back of the watch that permits views of the timekeeping mechanism at work.