Nicholas gives reasoning for having a style guidelines based on his past experiences and specific examples of how they can help. The most amazing thing about this section is that he managed to stay very unbias in a part of programming that most people become religious about. The level headed advice in this section is something any organization can take in and use.
I was surprised on how many little things I picked up from this section. What I really enjoyed was that he explained why and not just how you should do and not do certain practices. Not only does he highlight bad practices, but gives several solutions to overcome them. This was my favorite section by far.
There were also two appendices: an example style guide and a list of tools. Both of these are good references.
Written by Greg Babiars who builds things for the web. You can follow me on Twitter.