diff --git a/core/modules/book/templates/book-all-books-block.html.twig b/core/modules/book/templates/book-all-books-block.html.twig
index 6160982..a4d0c9a 100644
--- a/core/modules/book/templates/book-all-books-block.html.twig
+++ b/core/modules/book/templates/book-all-books-block.html.twig
@@ -18,7 +18,7 @@
  */
 #}
 {% for book in book_menus %}
-  <nav id="book-block-menu-{{ book.id }}" class="book-block-menu" role="navigation" aria-label="{% trans %}Book outline for {{ book.title }}{% endtrans %}">
+  <nav role="navigation" aria-label="{% trans %}Book outline for {{ book.title }}{% endtrans %}">
     {{ book.menu }}
   </nav>
 {% endfor %}
diff --git a/core/modules/book/templates/book-export-html.html.twig b/core/modules/book/templates/book-export-html.html.twig
index cbeb3b3..5fb2e97 100644
--- a/core/modules/book/templates/book-export-html.html.twig
+++ b/core/modules/book/templates/book-export-html.html.twig
@@ -37,7 +37,7 @@
     #}
 
   {% for i in 1..depth-1 if depth > 1 %}
-    <div class="section-{{ i }}">
+    <div>
   {% endfor %}
   {{ contents }}
   {% for i in 1..depth-1 if depth > 1 %}
diff --git a/core/modules/book/templates/book-navigation.html.twig b/core/modules/book/templates/book-navigation.html.twig
index abb0d31..0f12980 100644
--- a/core/modules/book/templates/book-navigation.html.twig
+++ b/core/modules/book/templates/book-navigation.html.twig
@@ -31,23 +31,23 @@
  */
 #}
 {% if tree or has_links %}
-  <nav id="book-navigation-{{ book_id }}" class="book-navigation" role="navigation" aria-labelledby="book-label-{{ book_id }}">
+  <nav role="navigation" aria-labelledby="book-label-{{ book_id }}">
     {{ tree }}
     {% if has_links %}
-      <h2 class="visually-hidden" id="book-label-{{ book_id }}">{{ 'Book traversal links for'|t }} {{ book_title }}</h2>
-      <ul class="book-pager">
+      <h2>{{ 'Book traversal links for'|t }} {{ book_title }}</h2>
+      <ul>
       {% if prev_url %}
-        <li class="previous">
+        <li>
           <a href="{{ prev_url }}" rel="prev" title="{{ 'Go to previous page'|t }}"><b>{{ '‹'|t }}</b> {{ prev_title }}</a>
         </li>
       {% endif %}
       {% if parent_url %}
-        <li class="up">
+        <li>
           <a href="{{ parent_url }}" title="{{ 'Go to parent page'|t }}">{{ 'Up'|t }}</a>
         </li>
       {% endif %}
       {% if next_url %}
-        <li class="next">
+        <li>
           <a href="{{ next_url }}" rel="next" title="{{ 'Go to next page'|t }}">{{ next_title }} <b>{{ '›'|t }}</b></a>
         </li>
       {% endif %}
diff --git a/core/modules/book/templates/book-node-export-html.html.twig b/core/modules/book/templates/book-node-export-html.html.twig
index 0efa9a7..39a41fc 100644
--- a/core/modules/book/templates/book-node-export-html.html.twig
+++ b/core/modules/book/templates/book-node-export-html.html.twig
@@ -15,8 +15,8 @@
  * @ingroup themeable
  */
 #}
-<article id="node-{{ node.id }}" class="section-{{ depth }}">
-  <h1 class="book-heading">{{ title }}</h1>
+<article>
+  <h1>{{ title }}</h1>
   {{ content }}
   {{ children }}
 </article>
diff --git a/core/modules/book/templates/book-tree.html.twig b/core/modules/book/templates/book-tree.html.twig
index 9f640d0..46068c7 100644
--- a/core/modules/book/templates/book-tree.html.twig
+++ b/core/modules/book/templates/book-tree.html.twig
@@ -13,4 +13,4 @@
  * @ingroup themeable
  */
 #}
-<ul class="menu">{{ tree }}</ul>
+<ul>{{ tree }}</ul>
diff --git a/core/modules/book/templates/book-all-books-block.html.twig b/core/themes/classy/book/book-all-books-block.html.twig
similarity index 100%
copy from core/modules/book/templates/book-all-books-block.html.twig
copy to core/themes/classy/book/book-all-books-block.html.twig
diff --git a/core/modules/book/templates/book-export-html.html.twig b/core/themes/classy/book/book-export-html.html.twig
similarity index 100%
copy from core/modules/book/templates/book-export-html.html.twig
copy to core/themes/classy/book/book-export-html.html.twig
diff --git a/core/modules/book/templates/book-navigation.html.twig b/core/themes/classy/book/book-navigation.html.twig
similarity index 100%
copy from core/modules/book/templates/book-navigation.html.twig
copy to core/themes/classy/book/book-navigation.html.twig
diff --git a/core/modules/book/templates/book-node-export-html.html.twig b/core/themes/classy/book/book-node-export-html.html.twig
similarity index 100%
copy from core/modules/book/templates/book-node-export-html.html.twig
copy to core/themes/classy/book/book-node-export-html.html.twig
diff --git a/core/modules/book/templates/book-tree.html.twig b/core/themes/classy/book/book-tree.html.twig
similarity index 100%
copy from core/modules/book/templates/book-tree.html.twig
copy to core/themes/classy/book/book-tree.html.twig