The name derives from the traditional white, button down shirts worn by workers of such professions. As white shirts are easily soiled, these workers do not do manual labor.
Formerly a minority in the agrarian and early industrial societies, the recent technological revolution has created disproportionatly more Desk jobs while America has experienced a decline in manufacturing. Generally, the pay rate is higher among white-collar workers, although many of the "white- collar" workers are not necessarily upper class as the term once implied.