Many of the windows you will see within TOPCAT display information about a single table. There are several of these, each displaying a different aspect of the table data - cell contents, statistics, column metadata etc. There is one of each type for each of the tables currently loaded, though they won't necessarily all be displayed at once. The title bar of these windows will say something like TOPCAT(3): Table Columns, which indicates that it is displaying information about the column metadata for the table labelled "3:" in the Control Window.
To open any of these windows, select the table of interest in the Control Window and click the appropriate toolbar button (or the equivalent item in the Table Views menu). This will either open up a new window of the sort you have requested, or if you have opened it before, will make sure it's visible.
If you have lots of tables and are using various different views of several of them, the number of windows on the screen can get out of hand and it's easy to lose track of what window is where. In this case the Control Window's Windows menu (described in Appendix A.2.6), or the Window|Control Window menu item in any of the view windows can be handy to keep them under control.
The following sections describe each of these table view windows in turn.