An Inquiry into the Nature and Causes of the Wealth of Nations

Chapter I: Of the Division of Labour

The greatest improvements in the productive powers of labour, and the
greater part of the skill, dexterity, and judgment, with which it is
anywhere directed, or applied, seem to have been the effects of the
division of labour. The effects of the division of labour, in the general
business of society, will be more easily understood, by considering in
what manner it operates in some particular manufactures. It is commonly
supposed to be carried furthest in some very trifling ones; not perhaps
that it really is carried further in them than in others of more
importance: but in those trifling manufactures which are destined to
supply the small wants of but a small number of people, the whole number
of workmen must necessarily be small; and those employed in every
different branch of the work can often be collected into the same
workhouse, and placed at once under the view of the spectator.

In those great manufactures, on the contrary, which are destined to supply
the great wants of the great body of the people, every different branch of
the work employs so great a number of workmen, that it is impossible to
collect them all into the same workhouse. We can seldom see more, at one
time, than those employed in one single branch. Though in such
manufactures, therefore, the work may really be divided into a much
greater number of parts, than in those of a more trifling nature, the
division is not near so obvious, and has accordingly been much less
observed.