diff --git a/app/models/book.rb b/app/models/book.rb
index 95c42dd..9b0358a 100644
--- a/app/models/book.rb
+++ b/app/models/book.rb
@@ -2,6 +2,7 @@
 class Book < ActiveRecord::Base
   attr_accessible :memo, :purchased_on, :title
   validates :title, :presence => true
+  has_many :memos, :dependent => :destroy
 
   before_create :total_books_count
 
diff --git a/app/models/memo.rb b/app/models/memo.rb
new file mode 100644
index 0000000..487736e
--- /dev/null
+++ b/app/models/memo.rb
@@ -0,0 +1,4 @@
+class Memo < ActiveRecord::Base
+  attr_accessible :book_id, :body
+  validates_length_of :body, :within => 1..100
+end
diff --git a/app/views/books/show.html.erb b/app/views/books/show.html.erb
index 23005ab..6c96569 100644
--- a/app/views/books/show.html.erb
+++ b/app/views/books/show.html.erb
@@ -15,6 +15,14 @@
   <%= @book.purchased_on %>
 </p>
 
+<%= link_to 'Add New Comment', new_book_memo_path(@book) %><br/>
+<% @book.memos.each do |memo| %>
+   <b> Comment: </b>
+   <%= memo.body %>
+   (<%= link_to "Delete", book_memo_path(:book_id => @book.id, :id => memo.id),
+       :confirm => "ok?", :method => :delete %>)<br/>
+<% end %>
+<br/>
 
 <%= link_to 'Edit', edit_book_path(@book) %> |
 <%= link_to 'Back', books_path %>
diff --git a/app/views/memos/new.html b/app/views/memos/new.html
new file mode 100644
index 0000000..c0c1f16
--- /dev/null
+++ b/app/views/memos/new.html
@@ -0,0 +1,7 @@
+Title: <%= @book.title %><br/>
+<br/>
+<%= form_for @memo, :url => book_memos_path do |f| %>
+   Add new Memo(with in 100 moji):<br/>
+   <%= f.text_field :body %><br/>
+   <%= f.submit %>
+<% end %>
diff --git a/config/routes.rb b/config/routes.rb
index f3d38ab..bafdadd 100644
--- a/config/routes.rb
+++ b/config/routes.rb
@@ -1,5 +1,7 @@
 BookMemo2::Application.routes.draw do
-  resources :books
+  resources :books do
+     resources :memos
+  end
 
   # The priority is based upon order of creation:
   # first created -> highest priority.
diff --git a/db/migrate/20120616050801_create_memos.rb b/db/migrate/20120616050801_create_memos.rb
new file mode 100644
index 0000000..f0350d9
--- /dev/null
+++ b/db/migrate/20120616050801_create_memos.rb
@@ -0,0 +1,10 @@
+class CreateMemos < ActiveRecord::Migration
+  def change
+    create_table :memos do |t|
+      t.integer :book_id, :null =>false
+      t.text :body
+
+      t.timestamps
+    end
+  end
+end
diff --git a/db/schema.rb b/db/schema.rb
index 5fc61c2..a1f1131 100644
--- a/db/schema.rb
+++ b/db/schema.rb
@@ -11,7 +11,7 @@
 #
 # It's strongly recommended to check this file into your version control system.
 
-ActiveRecord::Schema.define(:version => 20120526050801) do
+ActiveRecord::Schema.define(:version => 20120616050801) do
 
   create_table "books", :force => true do |t|
     t.string   "title"
@@ -21,4 +21,11 @@
     t.datetime "updated_at",   :null => false
   end
 
+  create_table "memos", :force => true do |t|
+    t.integer  "book_id",    :null => false
+    t.text     "body"
+    t.datetime "created_at", :null => false
+    t.datetime "updated_at", :null => false
+  end
+
 end
diff --git a/spec/models/memo_spec.rb b/spec/models/memo_spec.rb
new file mode 100644
index 0000000..7fdbc67
--- /dev/null
+++ b/spec/models/memo_spec.rb
@@ -0,0 +1,16 @@
+# coding:utf-8
+require 'spec_helper'
+
+describe Memo do
+    context "within 100 moji" do
+       body = "a"*100
+       subject {Memo.new(:body => body).valid?} 
+       it { should be_true }
+    end
+
+    context "more than 100 moji" do
+       body = "a"*101
+       subject {Memo.new(:body => body).valid?}                    
+       it { should be_false }
+    end
+end
diff --git a/spec/requests/books_spec.rb b/spec/requests/books_spec.rb
index 37522b7..62ad6b2 100644
--- a/spec/requests/books_spec.rb
+++ b/spec/requests/books_spec.rb
@@ -37,4 +37,34 @@
       end
     end
   end
+
+  describe '/books/:id/memos/new' do
+    let!(:book){FactoryGirl.create :book }
+    subject {page }
+
+    before { visit "/books/#{book.id}/memos/new" }
+    let(:memo_body){["hoge1","hoge2"]}
+
+    context "add 1memo" do
+      before do
+         fill_in "memo[body]", with: memo_body[0]
+         click_on "Create Memo"
+      end
+
+      it "resist check" do
+         should have_content(memo_body[0])
+      end
+    end
+
+    context "add 2memo" do
+      before do
+         fill_in "memo[body]", with: memo_body[1]
+         click_on "Create Memo"
+      end
+
+      it "resist check" do
+         should have_content(memo_body[1])
+      end
+    end
+  end
 end