Final Thoughts
No amount of reading books and tutorial is going to explain everything about UnrealScript to you. The lessons you've learned in this book are enough to get you started, but the best way to learn more is by experimenting with the code on your own. I really can't stress enough the importance of reading through the source code. Object, Actor, Controller, and Pawn are the four most important classes to read through. Reading through these classes, taking a look at the functions and variables they have that you can use, and seeing how they do things will help you understand how everything fits together in the UDK world.
Take your time, and be patient. Unless you're coming into UnrealScript with years of experience in another programming language, don't expect to create an entire game in a few weeks or even months. Personally, it took me a few years to get to the point where I felt comfortable programming an entire game using UnrealScript. Start small, creating variations on the weapons...