Virtualization is hot and Xen is one of the virtual machine managers (VMM), or hypervisors, that target the x86 platform. Xen is an open-source project, so it is readily available on the Internet and it is bundled with most current Linux distributions for platforms that support virtualization. Xen is tightly linked to Linux as is KVM, another VMM that is now part of Linux.
The book addresses the open source tools included with Xen. von Hagen does a good job of introducing virtualization including Xen alternatives—making the book ideal for novices.
Tools like Synaptics on Ubuntu or similar package management tools on other Linux distributions make setting up Xen a breeze but sometimes starting from scratch is a requirement so more advanced users will appreciate the attention to details and setup coverage.
Management is an ongoing, important issue represented well in this selection. von Hagan also expands on command-line tools and configuration files here, and he provides plenty of examples. I found the building file system and volume management discussions to be very useful as well.
A discussion on data center management wraps up the book. I would have liked more elaboration, but the book covers the topic well nonetheless.
Overall, this is one book that any network manager or developer dealing with Xen will want on the desk.