There are a few more Selection commands that can be found under the Select menu. For a sense of completion, let's take a quick look:
All: Pretty obvious... this command selects everything on the active layer or in your flattened document. The keyboard shortcut is Cmd+A (Ctrl+A) when the canvas window is selected.
Deselect: This command removes the active selection. You may need to do this when finished altering your selection to avoid accidentally modifying your image.
Reselect: This command is truly useful as it allows you to reactivate the last selection in your document. It only works with selections made since you've last opened the document.
Inverse: The concept of inverse is very important. It is often far easier to select what you don't want, then inverse the selection to get what you do want.
Let's try out the concept of Inverse, as well as some of the other commands:
Open the file wave.tif from the Chapter 5 folder.
Select the Magic Wand tool by pressing the W key.
Set the Tolerance to 30 and check the Anti-alias and Contiguous boxes.
Click the sky to make an initial selection.
Hold down the Shift key and click in another area of the sky to capture more.
When most of the sky is active, choose Select > Grow. If needed, repeat the command.
Choose Select > Inverse to capture the waves.