| From the Preface: "Our work here is divided into essentially two parts: Mathematical Foundation and Physical Principles. The separation is, of course, only nominal, and in developing the mathematical methods we must occasionally refer to physical concepts, e.g. spin characterization, which are not strictly defined until the work of the second part ... It is hoped that here the physicist may find the answers as to how and why a particular covariant formalism is suitable for the description of particles of given spin, and how and why the so-called field aspect of a given genus of particles is related to the so-called particle aspect---although this field-particle division is somewhat loose, or even redundant, outside the framework of the second quantization. As mentioned before, much of this material may be found in the literature, but it is hoped that the present review will sufficiently weed out and organize the subject matter as to provide a better basis for entry into current literature and research." |