No fluff, no BS, the book is an end-to-end walk through of Zabbix 1.8. As per the sysadmins motto from Alice in Wonderland, "Start at the beginning and go to the end. Then stop." That essentially sums up the book.
Start with installation and configuration, then moves into the fairly complex twists and turns of configuring your first hosts and items and then alerting. The official Zabbix manual is perpetially "under construction" and poorly handles some of these aspects, making this book especially essential.
Several Zabbix features can be very confusing to configure, such as graphing and notification escalation. Once you understand the concepts its easy, but doing it the first time can be a very time consuming affair. Being walked through these kinds of processes, step-by-step and addressing each possibility as it arises makes it quick, painless, and informative.
If your new to Zabbix or haven't used it since 1.4, I recommend you save yourself hours of fiddling around and just grab the book. You'll get things done right, the first time and help ensure your success with Zabbix.