This chapter presented a relatively quick review of the more important aspects of the Dow Theory. It will become clear, as you continue through this book, that an understanding and appreciation of Dow Theory provides a solid foundation for any study of technical analysis. Much of what is discussed in the following chapters represents some adaptation of Dow's original theory. The standard definition of a trend, the classification of a trend into three categories and phases, the principles of confirmation and divergence, the interpretation of volume, and the use of percentage retracements (to name a few), all derive, in one way or another, from Dow Theory.
In addition to the sources already cited in this chapter, an excellent review of the principles of Dow Theory can be found in Technical Analysis of Stock Trends (Edwards & Magee).