Yet another book that I started re-reading last week (but haven't finished again yet as it's so large) is Microsoft SQL Server 2008 Analysis Services Unleashed by Irina Gorbach, Alexander Berger and Edward Melomed.
This book has always left me with mixed feelings. The authors clearly offer expert level knowledge on the topics (as they were part of the development team for the product) but I struggle with the "readability" of this book. As an example, each time a concept is introduced, it is done so with accompanying XMLA code snippets, etc.I suspect that a lot of readers would be put off by the XMLA. Most people just don't think in XMLA.
The content of the book, however, is excellent. I normally tell classes that this is a great book to have as a reference on the product, but just not such a great book for reading from cover to cover. On re-reading it, that opinion hasn't changed.
If you're working with SSAS, you should have this book on the shelf for reference when required.
(And thanks to the publisher Sams for making it available in Kindle format)