I'm sure CouchDB is great, but this book, at least the first part, is really bad, full of half-truths and sometimes just plain wrong. I'm amazed O'Reilly is publishing this. Is there no editor involved to catch these mistakes?

In the section "Self-Contained Data" the author makes the argument that some data is better stored as a document than a bunch of relations, and uses INVOICES as an example: "Accountants appreciate the simplicity of having everything in one place. And given the choice, programmers appreciate that, too.". Invoices (and other business data) are the classical example of something that belongs in an RDBMS and not in something like CouchDB. It's not that hard to come up with a good examples for "relaxed data", like... say... blog posts, or blog comments, or twitter messages, or search results, or log entries?

Later, it gives incorrect/meaningless definitions for Consisteny, Availability and Partition Tolerance. It then completely confuses the CAP theorem, incorrectly placing Paxos (puts in under CA, should be CP). It also places RDMBSs on the figure, which is silly, "Relational Database Management System" in itself says nothing about how it is distributed, if even.

Part I/1+2 needs major rewriting.