Since the last edition of this book appeared the subject of International Trade has come into unexpected prominence. In the phraseology lately fashionable it has passed from the domain of "academic discussion" into the position of a "burning question." This chance is not altogether favourable to its treatment in a scientific manner. The greater part of the writing in the press and periodical literature is certain to be crude and ill-informed, the product of persons who have not taken the trouble to study the general principles that underlie the more obvious features of foreign commerce. The intrusion of party feeling is a further disturbing, influence. Where established principles stand in the way of a particular proposal its supporters will at once declare their disbelief in what they call "abstract theory," though they will readily use any of those principles that can be so distorted as to appear to serve their purpose.

It is, therefore, the more necessary to insist on the indispensableness of a general theory for the correct interpretation of the complicated phenomena of foreign . . .