People keep asking me about when we will publish the "definitive guide" book for symfony 1.4. We already have quite an extension documentation on symfony, but the definitive guide has a different way to teach you symfony that is best suited for some people. So, in the last few months, I have updated it to match the current version of symfony.
This updated version of "the book" is released under the GFDL license as was the original book (all other symfony books are covered by Creative Commons licenses). The license stipulates that all the material is under this license, except for the title, which is owned by APress, the original editor. That's why I have changed the title to "A Gentle Introduction to symfony".
So, with this new version of "the book", here is what you need to read, based on your needs:
Want to learn symfony? read the "Practical symfony" book if you want to learn by doing a real project or read the "Gentle introduction to symfony" if you want more theory and in-depth explanations of the main features;
Want to find everything about configuring symfony? Browse the "Reference guide" book.
Want to learn more advanced stuff? Browse the "More with symfony" book.
That's a lot of documentation for both beginners and advanced users. The symfony core team, some authors, and the translation teams spent a lot of time writing and translating documentation for the latest versions of symfony. And as a matter of fact, the symfony 1.3/1.4 versions are the most documented versions of symfony, ever.
So, why publish yet another book about symfony? The definitive guide book has some advantages over the existing books:
More time is spent describing the philosophy of the framework in the first two chapters (introduction to the MVC model, ...);
Each feature has its own chapter or section in the book. Looking for the documentation of a specific feature is easier (in the "Practical symfony" book for instance, it's more difficult to find things are they are described in the context of an application creation).
I have spent quite some time to update this book and we have some new chapters too: one about Doctrine (thank to Jon), one on forms (thank to François), and one on emails.