Amazon.com just posted my four star review of Professional Xen Virtualization by William von Hagen. From the review:
I really enjoyed reading Professional Xen Virtualization (PXV). The book answered exactly the right questions for me, a person who had no Xen experience but wanted to give the product a try. If you are looking for a book on Xen internals, you should read The Definitive Guide to the Xen Hypervisor by David Chisnall. If you are less concerned about source-code-level details but still want to learn a lot about Xen, you will definitely enjoy PXV.