This book aims to be a comprehensive Apache security resource. As such, it contains a lot of content on the intermediate and advanced levels. If you have previous experience with Apache, I expect you will have no trouble jumping to any part of the book straight away. If you are completely new to Apache, you will probably need to spend a little time learning the basics first, perhaps reading an Apache administration book or taking one of the many tutorials available online. Since Apache Security covers many diverse topics, it's likely that no matter what level of experience you have you are likely to have a solid starting point.
This book does not assume previous knowledge of security. Security concepts relevant for discussion are introduced and described wherever necessary. This is especially true for web application security, which has its own chapter.
The main thing you should need to do your job in addition to this book, is the Apache web server's excellent reference documentation (http://httpd.apache.org/docs/).
The book should be especially useful for the following groups: