It is obviously impossible in the limited space available to review historically the many researches that have led to vector electrocardiography, to summarize the numerous theoretical points of view, and to offer a critical evaluation of them, especially if even a tentative answer is to be found to the question: "Is vector cardiography worth while clinically now or will it ever be?" Instead of tackling this impossible assignment, we will limit the main presentation to just four topics. Each of these topics represents one major controversial area of the problem that can be evaluated separately in terms of individual experience; yet, taken together, these four topics include most of the vexing problems of present-day electrocardiography. Beside a few new numbers and theoretical relationships which we have to offer, our contribution to this symposium is primarily that of separating the variables of the problem into packages that are susceptible to individual