The origin of this research was an attempt to extend Cassel's system of equations of price determination in one market to that of several trading countries. Although the point of departure is totally different, the results of that attempt (presented in chapter III) exhibit important similarities to Heckscher's treatment in ‘‘The Effect of Foreign Trade on the Distribution of Income,'' published one year earlier in Ekonomisk Tidskrift, 1920. There is no doubt that the author was unconsciously influenced by Heckscher's paper both at this and at later stages of the work. The influence of this pathbreaking paper, both conscious and unconscious, has surely been particularly decisive in the development of the material in chapters I–III.