Abstract

In this chapter, we take a general look at the nature of photons and electrons (and of their interactions) in order to gain familiarity with their overall properties, in so far as they bear upon our subject. Clearly, it is useful to acquire this “feel” in general terms before getting immersed in some of the finer details, which, whilst very necessary, do not allow the interrelationships between the various aspects to remain sharply visible. The intention is that the familiarity acquired by reading this chapter will facilitate an understanding of the other chapters in the book.