Hi Dave, I've followed video tutorial but I don't know why it's not working. It doesn't pick autocomplete. From the server I get this message Processing by BooksController#create as HTML Parameters: {"authenticity_token"=>"[FILTERED]", "book"=>{"title"=>"I Malavoglia", "publish_year"=>"1881", "author_id"=>""}, "author"=>"Giovanni Verga", "commit"=>"Create Book"} and in the view I get the error message "Author must exist". I've created the application and pasted the code of your post. Can't understand where is the mistake.