There are several ways to use this book, but you will probably find that it is most useful when you want to see whether a shortcut is available for a particular tool or operation that you use a lot. Simply look in the index for that tool or command to find the page where the shortcut is listed. The shortcuts for both Macintosh and Windows versions of Photoshop will be listed.
Because several major releases of Photoshop exist, I've marked which versions (and which applications, because this book covers ImageReady) each shortcut will apply to. A solid box indicates the shortcut will work, and an empty box means it will not.