Seven Databases in Seven Weeks takes the reader through Redis, Neo4J, CouchDB, MongoDB, HBase, Riak, and Postgres. Though this is a sampling platter focused primarily on NoSQL databases (Postgres being the exception), the information packed in each chapter requires the reader to be fully engaged and participative in the learning process. The material is not suitable for those without a strong technical background - the occasional dabbler like myself will find themselves drinking from a fire-hose.
If my goal was to start working in these databases right after reading the book, I would be disappointed - not because the material is lacking but because I lack the required background. That said, I learned enough about to understand what business problems each was best set up to solve and that was a great outcome for me. The challenge would be to convince a client to try something non-traditional because NoSQL was a better solution for their problem. Then there would be the question of easy access to the talent pool to actually do the work.
If you had each of these databases successfully installed and running on your machine and the desire to learn, you could make it through all the exercises in seven weeks. I am going to assume that a reader who did that would be very well set up to use these databases on live projects.
The best thing this book does, is to bring awareness around the distinct flavors of NoSQL databases (unlike SQL databases, they are not variants of the same standard) and help clarify the differences between them.