Book excerpt: This is an extensive course for the gann trader as well as the investor. W. D. Gann's Stock Trading Course can teach you a number of different trading techniques and skills, such as charting, chart interpretation, how do find natural resistance levels, forecasting trend changes, using Gann Lines (or Gann Angles), seasonal changes for stocks, how to decipher time cycles, the relationship between time and price, squaring price and time, how to use gann squares & gann calculators and more.