[영문]The subject of this Ruggles Lecture is the distribution of earnings amongindividuals. It is concerned with how much different people earn, and how earningsdifferences have changed over time. I am sure that it will be agreed that thisis a subject which should be central to economics. It is certainly of widespreadinterest among the general public, as recognized in the above quotation fromEmployment in Europe 2005. It is also a topic that has attracted a lot of attentionfrom economists in recent years. A major reason for this interest was the realizationin the United States that earnings dispersion had started to increasesharply around the end of the 1970s. Figure 1 shows the decile ratio for individualgross earnings in the U.S., which rose over this period from about 3.6 in1980 to around 4.4 in the 1990s. (Here, as in the rest of the Lecture, I amconcerned with the bulk of the distribution, from the 10th to the 90th percentile,not with the very top.)Much of the considerable resulting literature has been concerned withexplaining the rise in the decile ratio in the U.S., and the changes in other OECDcountries, since the 1970s. To take two recent examples, the article by Gottschalk