The end of a century is a time for looking back, evaluating and reminiscing. Most of all, it seems, it's a time for making lists. By now, we all know the names of the 100 best books, best movies, and biggest news stories of the 20th century. So, in the enumerative spirit of the times, we present here the 20 most important wristwatches of the 20th century.

What do we mean by important? Several things. Some of the watches are on the list because they represent technological breakthroughs. Others because of their innovative design. Others because of their enduring popularity and still others because they were, quite simply, examples of watchmaking virtuosity.

We enlisted a panel of three experts to help us compile the list. They are Osvaldo Patrizzi, founder and head of the Geneva-based auction house Antiquorum, which has been specializing in timepieces since the mid-1970's. Antiquorum is the biggest watch-auction house in the world and Patrizzi one of the world's best-known watch historians.

Charles Cleves, a long-time watch dealer, collector, and authority of vintage wristwatches. His store, Cleves and Lonnemann, is in Bellevue, Ky.

Roland Schild, and expert on Swiss watches and the modern Swiss watch industry. Schild, now retired, spent 30 years as a media consultant to Swiss watch associations and firms. Darwel S.A., the firm he co-founded in 1969, is the Swiss watch industry's top public relations firm.

Each panelist compiled a list of what he regards as the most important wristwatches of the century. So did we. We compared the lists and, after weighing the arguments made on behalf of the contenders - and there was considerable disagreement among our panelists - chose 20 of them. The final decisions were based on suggestions from the panelists but were, ultimately, ours alone.

The watches are presented in alphabetical order except for the last, the Watch of the Century (which all the panelists agreed on, as did everyone else whose opinion we asked).