Toad for Data Analysis has an Object Palette that shows numerous objects associated with the data source you're working with.  In the case of Excel spreadsheets, the Table tab will show the contents of the Excel file that have been specified as named ranges.  What do you do if you aren't using named ranges in your Spreadsheet?

Believe it or not, there's an answer.  From the Tools menu, select Options.  Navigate to Database->Odbc.  Check the box labeled Show system objects.  Now, establish the connection to the spreadsheet that doesn't have named ranges.

In the Table tab of the Object Palette, you'll see a folder named System Tables.  When you expand the folder, you'll see the various sheets in your workbook.  The sheets will be labeled Sheet1$, Sheet2$, etc.  Problem solved!