saving data of some other model

I have two models. Books Authos

books... has_many :authors

now you can add author through authors controller after selecting a book.

but I also want to be able to add author through book's new/edit form. like there is a field in which I can provide authors names so that those would be stored in authors table with this book_id.

I am not really sure how to do this while I am using book controller.