This is a study of the changing size of occupational classes, of their concomitant pay structure and the timing and circumstances of changes in this structure, in the period 1906–1960. In marshalling the facts about the numbers of people in the various broad occupational classes, Dr Routh has indicated the rise or fall of numbers in the occupations of which each class is composed, and the relation of these changes to the changing industrial structure of the economy. He also shows changes in participation rate by age and sex over the half-century, and makes some comparisons of the broad occupational structure of Britain with that of some other countries.