al author is David Weis, an expert in the Wyckoff Method. The Weis Wave is a modern adaptation of the 1930’s Wyckoff Method, another expert in Tape Reading techniques and Chart Analysis. Weis Waves takes market volume and stacks it into waves according to price conditions giving the trader valuable insights about the market conditions.
If you want to learn more about this subject you can find tons of videos in YouTube. Just look for “The Wickoff Method”, “Weis Wave” and “Volume Spread Analysis”.
There is also the book David Weis wrote himself called “Trades About to Happen” (Wiley Trading Series).