When I received a review request for Plone 3 Products Development Cookbook from Packt, the first thing I thought was: How didn’t I know about this book before, and who are the authors? I’d certainly not heard about them (Juan Pablo Giménez and Marcos F. Romero) nor this upcoming book ever before, but it seems there are a lot of Plone books being written behind the scenes by people not hanging at #plone too. 
The list of reviewers, comprising Martin Aspeli, Alec Mitchell and Emanuel Sartor, being as they are core and very active developers, automatically made me think this was going to be an accurate and up-to-date book.
This is the second book in the market about modern development with Plone, after Martin Aspeli’s Proffessional Plone Development. And after having skimmed through it (if you try to proof-read this kind of books from top to bottom your brain can explode), I can say that it’s probably going to become a classic invaluable reference as PPD already is.
Plone 3 Products Development Cookbook spans over 350 pages full of useful tips, set-up instructions and step-by-step coding approaches to solve specific use-cases (that’s why it’s called “cookbook”). Even if the book title says Plone 3, I think it’s just a Packt policy – one can be sure that most of the contents (if not all them) will be valid for Plone 4 too, and the authors even included some special instructions for Plone 4.
The book show-cases the development of an hypothetical digital newspaper with Plone, covering the whole process: From installing Python and Plone in Linux or Windows (Mac OSX specifics aren”t covered in this book) to preparing the production environment, passing through the installation of useful development tools like ipdb, DocFinderTab or plone.reload, creating content-types using ArchGenXML, paster-aided plain Archetypes or Dexterity, internationalizing and localizing the product, building XML-RPC interaction with other systems, and more (see the full table of contents). All the features coded include automated tests, what is a Very Good Practice and will help devs to be less afraid of writing tests.
The book is organized in a recipe-list fashion, in chapters, every recipe including “getting ready”, “how to do it”, “how it works” and “there is more” sections. Sometimes the separation of concerns between these sections is not very clear, but one can expect a series of short steps in “how to do it”, to use as reference, and some brief explanation in “how it works”.
In my opinion, this is not a book for beginners. Even if there are some explanations in the “how it works” section of each recipe, they are almost always quite brief, and can certainly make you have to re-read and Google for more documentation often, if you really want to understand how the Zope Component Architecture, ZPT, skin layers, z3c.forms, etc. work. I see it more as a reference book for more advanced developers, who can also discover in this book some tricks and approaches they didn’t know before – I certainly did!
Summing up, this is a really useful reference for folks with previous developing experience in Plone. My sincere congratulations to the authors for their hard work to make this happen – I’m sure it will hit the shelves of every active Plone developer!