There are many objects, properties, collections, and methods available in the Excel object model that were not covered here. It is probably worth several hours of time just to peruse the Excel Object Model through Microsoft Visual Basic Help or the Object Browser. Search for keywords to determine where the particular property, method, object, or collection is located. Based on where it is located, determine how to access the item. Also, in the help window, you are often given a small snippet of code that demonstrates how to use the item.
I often find very neat ways to code functionality into Excel by finding a method that I didn't know about. Keep in mind that each of the objects, properties, and collections in the Application, Workbook, Worksheet, etc. objects have their own objects, properties, collections, and methods. I also encourage you to check out many of the online resources offered by Microsoft; in Office 2003, the help window can be set to search the online content. Often, you can download examples that you can learn a lot by going into the code. Finally, in the main text of the book, I let you know that by using the Macro Recorder, you can see how to program many items. I just want to reiterate that here because if you know how to do something via the Excel User Interface, you are just the Macro Recorder away from learning how to code the same task.