Overview
Volume is simply the number of shares (or contracts) traded during a specified time frame (e.g., hour, day, week, month, etc).  If volume is reported for the security, MetaStock for Java automatically plots it along the bottom of the chart as a histogram. The analysis of volume is a basic yet very important element of technical analysis.  Volume provides clues as to the intensity of a given price move.

Interpretation
Low volume levels are characteristic of the indecisive expectations that typically occur during consolidation periods (i.e., periods where prices move sideways in a trading range). Low volume also often occurs during the indecisive period during market bottoms.

High volume levels are characteristic of market tops when there is a strong consensus that prices will move higher.  High volume levels are also very common at the beginning of new trends (i.e., when prices break out of a trading range).  Just before market bottoms, volume will often increase due to panic-driven selling.

Volume can help determine the health of an existing trend.  A healthy up-trend should have higher volume on the upward legs of the trend, and lower volume on the downward (corrective) legs. A healthy downtrend usually has higher volume on the downward legs of the trend and lower volume on the upward (corrective) legs.