In the 3D Analyst book, Exercise 2, page 19, step 1, you get a warning message when you right-click the raster called "congrd" and click properties.
The message is:
This dataset has more than 2048 unique values, a raster table will not be built. The "Unique Values" renderer and the "Fields" and "Joins & Relates" tabs will not be available for this dataset.
This is a notice that there are too many unique values in the data for ArcMap to make a VAT for the raster. That is ok, it is continuous floating-point (not categorical) data, and it doesn't need a VAT.
Click OK on the warning message box and continue.