After reading the sample introduction page it seems suspect. Its going to have you going through your system disabling things that are actually useful, and might actually make a difference if you're on a fairly old machine. I'd also put money on this content being available all over the internet for free and not entirely applicable.
An excerpt:
In chapter 2, you're shown the required syntax for stopping the execution of Automatic Termination, Dashboard, Finder, Mission Control and Spotlight and removing them from memory. In Chapter 3, you're guided through the appropriate selections in System Prefs for Language & Text, Security & Privacy, Spotlight, Users & Groups and Time Machine to remove data within those programs from memory. And in chapter 4, you're taught the basis for making the appropriate decisions regarding the usage of journaling and how to repair disk permissions to improve the sound of your Mac.