Good Book , as most of the topics are well covered , Not for beginners though For beginners i would recommended The Black Book Series . All in all Good book ( if u know basics of SQL Server previously)

Well, as you know the author and her achievement, there is no second thoughts on the content and its depth of the information coverage. This book expects you (as a reader) that you know your stuff and you know what you are looking for - then this books becomes really easy access. Even though the reader is learning and in the preliminary stage still this book gives you the expert knowledge and makes sure the foundation your are laying is stronger already.

There are two books on Internals, one...

Must have book for DBAs and people especially looking out for better understanding SQL Server engine.

In depth

Contents in the book are well organized. Must to have for all SQL professionals.
For beginners it may be hard, but repeated reading will gain you lot. Go for it.

Kudos to Kalen Delaney!!

This is the finest book I have gone through for SQl Server. Every DBA, or anybody who wants to be a DBA needs to go through this. There are minute details about how SQL Server works. Usually, when we are talking about such topics, we expect something very complicated, something that only experienced people can understand, but that is not the case here. Even someone with very basic idea of RDMS can understand this. This is a must read.