Now is the time for something like Halo 2 Hacks. The fans have ripped it apart inside and out, and this book goes deeper. While it starts somewhat like a strategy guide, it quickly dives into actual hacking of the game's code. This is where you can have the most fun with the game, creating textures, maps, and new features for weapons.
The first five chapters offer some basic information on the game, things that were quickly discovered when the game released. The difference in Halo 2 Hacks is the details, digging a little deeper as to what the hidden skulls do and why. Easter eggs offer some fun items to watch for, including a funny cut scene involving dancing Grunts. Glitches are focused on, though whether or not you find them useful depends on your feelings towards cheating (and that's not what the book is about actually).
The book then moves into the complicated range, including how to hack into the game's code to make your own changes. You'll need at least a basic knowledge of the software used (ADI). There is a brief rundown of the program, but it's probably not enough to start hacking into the levels without a little familiarity. Of course, a modded Xbox is necessary too.
These mods are split into multiple sections, including weapons, vehicles, levels, display, and gameplay. There are significant changes to be found here. The battle rifle zoom is a great one, nearly tripling the guns zoom feature for incredible accuracy. You can adjust various physics, weapon strength, and even the lighting intensity. Finishing the process is a chapter on actually creating completed levels and inserting your own touches.
It's laid out nicely, with full color pictures that are necessary to learning the process. The book's binding and odd size (8.9 x 6) is the biggest complaint. Trying to follow these hacks step-by-step is unbearably hard, the tight binding slamming the book shut every time you take your hand away.
Halo 2 Hacks is a book for someone who is already involved in the process, even if it's only slightly. Those who have been doing this for a while will likely know the process already; those who have made minor tweaks will find this to be invaluable in creating their own vision for the game. You'll likely have more frustration trying to hold book open while typing in changes than you will with the process. It's made that easy.