XenSource's Senior Director of Products and Solutions Marketing, Roger Klorese, writes on his blog site that Xen books are out and more are coming.  He writes:

One of the key signs that a product or technology has moved beyond the “who?” phase into the “I’ll take two” phase is the appearance of independent writing about it. When I was at Veritas, for instance, we started our own imprint to bring out books on relevant areas, but the appearance of third-party NetBackup, SAN and Cluster Server books were the real proof points.

So I’d view the publication of David E. Williams and Juan Garcia’s Virtualization with Xen: Including XenEnterprise, XenServer, and XenExpress as a great step forward even if the book were not as comprehensive and skillfully executed. It includes an overview of virtualization; a deep dive into Xen’s architecture; a rich examination of open source Xen, the commercial products, and third party tools; and lots more. It even includes copies of the XenExpress 3.2 main and Linux support CDs!

Read his entire post and comment on it, here.