Getting to Know ArcGIS
GIS is a massive topic. You can spend your entire lifetime studying this field and still not know it all. And on top of that, studying can only get you so far. You will begin to learn so much more by taking the initiative to explore hands on above and beyond any textbook.
Even though I feel you can learn more by exploring, I would suggest you take a look at the Getting to Know ArcGIS Desktop book. This book is full of rich information covering GIS in the ArcGIS software environment. The basics of ArcView, ArcEditor, and ArcInfo at version 9 are covered. And it is obvious that this book cannot keep up with technology because later versions have already come out. And although this is true, version 9 basics apply across the board even if you are using 9.3 or later. I cannot stress enough the importance of know these basics since they will be your foundation of any building block you may apply.
Explore it today and build a foundation for your future.