Microsoft's new "Exam Ref" series will be a brilliant set of books, if Designing Messaging Solutions with Exchange Server 2010 is anything to go by. A relatively new initiative by MS Press, the Exam Ref series is designed to be concise, allowing for efficient and quick study. This book certainly meets that criteria. Definitely not content for a beginner Exchange admin, this book is geared towards those who have been Exchange admins for some time, who are looking to either design their own solutions from scratch, or just pass the 70-663 exam.
This book is a fantastic guide for experienced Exchange administrators who want to upgrade their skill-set to designing Exchange solutions, rather than simply managing and supporting them. The book goes in depth to detail *why* something is done a particular way, rather than just telling the reader to "do it", providing a much more fundamental understanding of the product. Focus is placed particularly on the enterprise features of Microsoft Exchange Server 2010, covering topics such as: Federation; multiple forest use; cloud synchronisation and in-depth routing information. This is not a book for the beginner Exchange administrator, but if you already have an implementation or are working to design solutions using Exchange 2010, this is a must-have.
The author's experience with the product is obvious with gotchas and useful tips present throughout. Designing and Deploying Messaging Solutions with Exchange Server 2010 closely follows the requirements of the 70-663 MCITP exam, so even if you're only in it to pass the exam, this is an extremely useful resource.