class Controller_Test extends Controller {
    public function action_list($offset = NULL) {
        $books = new Books();
       print_r($books->get_list($offset));
    }
}

----

 public function get_list($start = null) {
        if ($start == NULL) {
            $offset = 0;
        } else {
            $offset = $start * 30;
        }
        $books = array();
        $book = Model_Book::query()->limit(30)->offset($offset)->get();

        foreach ($book as $b) {
            \Arr::insert($books, $b, 0);
        }
        return $books;
    }