White Collar by C. Wright Mills — Read

THE LABOR FORCE: 1870 - 1940 / Old Middle Class: 33% - 20% / New Middle Class: 6 - 25 / Wage-Workers: 61 - 55 / Total: 100% - 100%

Of the three broad strata composing modern society, only the new middle class has steadily grown in proportion to the whole. Eighty years ago, there were three-quarters of a million middle-class employees; by 1940, there were over twelve and a half million. In that period the old middle class increased 135 per cent; wage-workers, 255 per cent; new middle class, 1600 per cent.*