Unfortunately, as with most books in this genre (OODB), the examples and explanations are limited to very simple designs. Furthermore, even the small amount of information dedicated to the design explanations is not enough to wet the appetite for even the most inexperienced individuals.
Removing the 'install' chapter and adding a chapter to dissect a simple 'Address' database with embedded lists of phones, addresses, emails, relationships, and more would go a LONG way. It is disappointing that the authors took the typical beginners approach to a subject that many relational database bigots are dying to beat up on. By not showing a direct comparison to a relational design (function by function, attribute by attribute) they have left InterSystems with little to demonstrate to their potential customers why Cache is a powerful alternative to the status quo.
Shame... Could have been such a terrific book and demonstrative example of how and why OODBs will eventaully rule the real world. Until then we will have to wait for the sequel and hope that it can address the shortcomings of this book.