This document discusses various indicators related to volume, open interest, and breadth in financial markets. It provides explanations of common volume indicators like average volume, force index, volume oscillator, on-balance volume, and how they are calculated and interpreted. It also discusses open interest, breadth, equi-volume charts, Herrick payoff index, and how volume can be used to predict volatility and divergences in price trends. The document serves as a guide to the basics and applications of these important technical analysis tools based on volume and market participation data.