(edit: trying to get the links into the this review for people rather than the [...] magic.)
That means the entire source for the book is available online.
If you really like the content and want to give the authors money by all means please buy this book. The ideas contained in there are useful and having them laid out like this can save you time. If you just need the knowledge (or even better want to contribute to the book!) then
You can use that source to build your own epub/pdf/html/latex version of the book. Problem of course is getting said build to your device, but if you're reading this book I'm going to assume you can figure that one out =)
Now for the actual content review.
This books isn't design patterns a la the GoF (isbn: 0-201-63361-2), it's more like a collection of guidelines. There are some code examples but they're somewhat sparse. One big thing to be aware of is that some of the guidelines are not Django 1.3-esque. Case in point, the section on generic views. In Django 1.3, generic views as functions are suppose to be replaced with their class based views brethren. There are other places where the idea is presented but pretty much left as an exercise to the reader i.e. Audit Trail and rollback.
Enough criticism, the really useful sections that I wish I had known about as a newbie to django?
settings.py and localsettings.py, custom manager methods and using pdb remotely. Those three things would have saved me some pain early on.
The ideas presented are helpful and definite food for thought. Just don't expect fully fleshed out examples in this book.
p.s. Quick shout out to Python Weekly [...] for sending me over to this book.
pps Amazon, the restrictions on not posting links in reviews to relevant content? Annoying.