Ruby on Railsでform_forのエラー

前提・実現したいこと

Railsで初めて、投稿サイトのようなものを四苦八苦しながら作成しております。

発生している問題・エラーメッセージ

ArgumentError in Books#index
Showing /home/vagrant/work/Bookers/app/views/books/index.html.erb where line #35 raised:

First argument in form cannot contain nil or be empty

33 <h2>New book</h2>
34 <div class="new">
35 <%= form_for(@book) do |f| %>
36 <%= render partial: "layouts/error_message", locals: {model: @book} %>
37     <div class="new-book">
38         <%= f.label :title %><br>

該当のソースコード

index.html.erb

Ruby:(index.html.erb)
1<div class="index">
2<h1>Books</h1>
3<table>
4	<thead>
5		<tr>
6			<th>Title</th>
7			<th>Body</th>
8		</tr>
9	</thead>
10	<% @books.each do |book| %>
11	<tbody>
12	    <tr>
13			<td>
14		        <%= book.title %>
15			</td>
16			<td>
17		        <%= book.body %>
18			</td>
19			<td>
20				<%= link_to "Show", book_path(book) %>
21			</td>
22			<td>
23				<%= link_to "Edit", edit_book_path(book) %>
24			</td>
25			<td>
26				<%= link_to "Destroy", book_path(book),method: :delete, "data-confirm" => "Are you sure？" %>
27			</td>
28		</tr>
29	</tbody>
30	<% end %>
31</table>
32
33<h2>New book</h2>
34<div class="new">
35<%= form_for(@book) do |f| %>
36<%= render partial: "layouts/error_message", locals: {model: @book} %>
37    <div class="new-book">
38        <%= f.label :title %><br>
39        <%= f.text_field :title %>
40    </div>
41    <div class="new-book">
42    	<%= f.label :body %><br>
43        <%= f.text_area :body %>
44    </div>
45    <div class="btn">
46    	<%= f.submit 'Create Book' %>
47    </div>
48<% end %>
49</div>
50

books_controller.rb

Ruby:(books_controller.rb)
1class BooksController < ApplicationController
2  
3  def top
4  end
5
6  def index
7    @book = Book.new
8    @books = Book.all
9  end
10
11  def create
12    book = Book.new(book_params)
13    if book.save
14       flash[:notice] = "Book was successfully created."
15       redirect_to book_path(book.id)
16    else
17       @book = book
18       @books = Book.all
19       render :index
20    end
21  end
22
23  def show
24
25    @book = Book.find(params[:id])
26  end
27
28  def edit
29    @book = Book.find(params[:id])
30  end
31
32  def update
33    book = Book.find(params[:id])
34    if book.update(book_params)
35       flash[:notice] = "Book was successfully updated."
36       redirect_to book_path(book.id)
37    else
38       @book = book
39       render :edit
40    end
41  end
42
43  def destroy
44    book = Book.find(params[:id])
45    book.destroy
46    flash[:notice] = "Book was successfully destroyed."
47    redirect_to books_path
48  end
49
50  private
51
52  def book_params
53    params.require(:book).permit(:title, :body)
54  end
55
56end