We've already talked about quite a few topics in the previous chapters, but we have been purposefully omitting an important aspect in many of them--access control. Much of what we covered deals in some way or another with access, but we have kept it out of our discussions to keep things more to the point. However, access control is an immensely important topic for Drupal development because it has implications in almost everything we do. So, for this purpose, we have a chapter dedicated to it in which we will cover the most important things you need to know in order to keep your application secure.
When I say secure I don't mean writing code in a secure way to avoid your site getting hacked. For that, we have an appendix at ...