I''m using nested attributes in a new project, but struggling with one issue. Imagine, for example you have the models User, Book, and Shelf. A user has_many books, and has_many shelves. A shelf also has_many books. User accepts_nested_attributes for books and shelves, and shelves accept them for books. So, if I were to do something like the following pseudo code: shelf = @user.shelves.find([some conditions]) book = shelf.books.new([some params]) book.save() In this case, the book should be correctly associated with the shelf, but it''s not associated with the user. Is there a way to automatically have the book be associated with the user that the shelf was associated with when the book is created like this? Perhaps through a callback? Just wondering if there''s a standard way to do this before I go re-inventing anything. Thanks :) M@ -- Posted via http://www.ruby-forum.com/.