QUOTED FROM" http://www.sapereonline.com/dictionary.html
"The final set of data dictionary objects are not intended for direct access by most users or commonprograms. Over 1,000 of these views (called fixed views) have names beginning with V$ or GV$. (TheV$ views provide information about the instance you are connected to while the GV$ views providea global view of all instances within a Real Application Clusters database environment.) Monitoringand tuning tools as well as SQL scripts developed by system DBAs will commonly select from theseV$ and GV$ views. Developers without access to these tools may find useful tuning information insome of these views such as V$SQLAREA and V$SYSSTAT. (Access to these views is, by default,restricted so developers will generally have to be granted the SELECT ANY DICTIONARY system privilegeby a DBA before they will be able to view this information.)"