PREFACE 
THis volume is divided into three parts. Part I takes up the theory 
of international trade. It restates views commonly held, with some 
amplifications and corrections. Part II is directed to ascertaining 
how far the actual commerce between nations proceeds in accord with 
that theory — how far the abstract conclusions are verified in the 
observed phenomena. Part III examines the characteristics of inter- 
national trade between countries not having the same monetary 
standard; the previous Parts having been concerned with trade 
between countries having the same (gold) standard. 
Part I follows in the main the lines of analysis and exposition which 
Ricardo initiated. The theorems are presented in a numerical form 
similar to that which he was the first to use. And not merely is 
Ricardo’s method of exposition followed ; the deduced conclusions are 
of the same kind as his. No part of that remarkable man’s work was 
more original than his brief but pregnant analysis of international 
trade, and none has dominated the course of subsequent discussion 
so largely. His loyal disciple, the younger Mill, began the task of 
supplementing and enlarging the Ricardian theory; subsequent 
writers have elaborated and refined still further; yet always — so far 
as they have done anything constructive, — on the same fundamental 
lines.! I cannot pretend to have made any contribution of large 
significance in this part of the field; tho I hope that something in the 
way of enrichment may be found. The task of preparing a systematic 
statement has led not merely to the repetition and elaboration of 
propositions well understood, but also to some conclusions which 
previous writers seem to have ignored. 
1 See the remarkable comments on the literature of the subject, both mathematical 
and non-mathematical, by Edgeworth, in his essays on International Values, 
printed in Volume 2 of his Collected Papers. Compare with this the rounded and 
searching treatment of the same literature, old and new, by Professor J. W. Angell, 
in his book on The Theory of International Prices, a book which unfortunately 
did not reach me until the text of the present volume had been completed.