That's right, there's an entire book about SilverStripe CMS. Written by SilverStripe core developer Ingo Schommer with the help of designer, programmer and writer Steven Broschart, the book is a 450 page long guide to SilverStripe for Web developers with an intermediate familiarity with website development, PHP5, and object oriented code.
The company put out a call for writers specifically for the project in March 2008. Merely a year later they've not only kicked it out, they' also managed to land on Amazon.de's CMS bestseller list within two weeks of release.
We would say we're surprised, but given that the company just won the Most Promising Open Source Content Management System award from Packt Publishing, we're not. The folks over at SilverStripe are definitely on top of things.
For now, the guide is only in German (bummer) but SilverStripe has stated that they're exploring the idea of an English translation in the near future.