renderでNoMethodErrorが発生します

バリデーションにかけて、空白のまま投稿した際にrenderでindex.html.erbを表示したいのですが、NoMethodErrorが起きてしまいます。
変数の名前が重複しているのがエラーの原因と推測しています。

エラー文↓

Shutaコントローラ↓

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

index.html.erb↓

Rails
1<h1>Books</h1>
2
3<table class="table">
4  <thead>
5    <tr>
6      <th>Title</th>
7      <th>Body</th>
8      <th colspan="3"></th>
9    </tr>
10  </thead>
11  <tbody>
12    <% @booker.each do |book| %>
13     <tr>
14       <td>
15        <%= book.title %>
16       </td>
17       <td>
18        <%= book.body %>
19       </td>
20       <td>
21         <%= link_to "Show", shutax_path(book.id) %>
22         <%= link_to "Edit", edit_shutax_path(book.id) %>
23         <%= link_to "Destroy", destroy_shutax_path(book.id), method: :delete, data:{ confirm: "Are you sure?" } %>
24       </td>
25     </tr>
26    <% end %>
27  </tbody>
28</table>
29
30
31
32<h1>New book</h1>
33
34<% if @book.errors.any? %>
35  <%= @book.errors.count %>
36  <% @book.errors.full_messages.each do |message| %>
37    <%= message %>
38    <% end %>
39<% end %>
40
41
42
43<%= form_with model: @book, url:'/books', local:true do |f| %>
44  <h4>Title</h4>
45  <%= f.text_field :title %>
46  <h4>Body</h4>
47  <%= f.text_area :body %>
48  <%= f.submit 'Create Book' %>
49<% end %>