Yesterday I posted a patch to the book module that allows site admins to mark some books as "protected". Whereas users with appropriate permissions can edit, outline... normal books, only users with an additional "edit protected books" permission can work with protected books.
I've seen many people asking for something like this, I hope this can help someone. Please review and give feedback.
A very simple, but to me puzzling question: why are comments stored in a seperate table instead of in the "node" table? It would make, for instance, tracking posts of a user much easier.