Nations tolerably well advanced as to skill, dexterity, and judgment, in the application of labour, have followed very different plans in the general conduct or direction of it; and those plans have not all been equally favourable to the greatness of its produce. The policy of some nations has given extraordinary encouragement to the industry of the country; that of others to the industry of towns. Scarce any nation has dealt equally and impartially with every sort of industry. Since the downfall of the Roman empire, the policy of Europe has been more favourable to arts, manufactures, and commerce, the industry of towns, than to agriculture, the industry of the country. The circumstances which seem to have introduced and established this policy are explained in the third book. Though those different plans were, perhaps, first introduced by the private interests and prejudices of particular orders of men, without any regard to, or foresight of, their consequences upon the general welfare of the society; yet they have given occasion to very different theories of political economy; of which some magnify the importance of that industry which is carried on in towns, others of that which is carried on in the country. Those theories have had a considerable influence, not only upon the opinions of men of learning, but upon the public conduct of princes and sovereign states. I have endeavoured, in the fourth book, to explain as fully and distinctly as I can those different theories, and the principal effects which they have produced in different ages and nations. To explain in what has consisted the revenue of the great body of the people, or what has been the nature of those funds, which, in different ages and nations, have supplied their annual consumption, is the object of these four first books. The fifth and last book treats of the revenue of the sovereign, or commonwealth. In this book I have endeavoured to shew, first, what are the necessary expenses of the sovereign, or commonwealth; which of those expenses ought to be defrayed by the general contribution of the whole society, and which of them, by that of some particular part only, or of some particular members of it: secondly, what are the different methods in which the whole society may be made to contribute towards defraying the expenses incumbent on the whole society, and what are the principal advantages and inconveniencies of each of those methods; and, thirdly and lastly, what are the reasons and causes which have induced almost all modern governments to mortgage some part of this revenue, or to contract debts; and what have been the effects of those debts upon the real wealth, the annual produce of the land and labour of the society. BOOK I. OF THE CAUSES OF IMPROVEMENT IN THE PRODUCTIVE POWERS OF LABOUR, AND OF THE ORDER ACCORDING TO WHICH ITS PRODUCE IS NATURALLY DISTRIBUTED AMONG THE DIFFERENT RANKS OF THE PEOPLE. CHAP. I. OF THE DIVISION OF LABOUR.