diff --git a/RMuseum/Models/PDFLibrary/Book.cs b/RMuseum/Models/PDFLibrary/Book.cs
new file mode 100644
index 00000000..ac6a017e
--- /dev/null
+++ b/RMuseum/Models/PDFLibrary/Book.cs
@@ -0,0 +1,31 @@
+using RMuseum.Models.Artifact;
+using System.Collections.Generic;
+
+namespace RMuseum.Models.PDFLibrary
+{
+    /// <summary>
+    /// a book might have different PDFBook or MultiVolumePDFCollection instances
+    /// </summary>
+    public class Book
+    {
+        /// <summary>
+        /// Id
+        /// </summary>
+        public int Id { get; set; }
+
+        /// <summary>
+        /// book name
+        /// </summary>
+        public string Name { get; set; }
+
+        /// <summary>
+        /// description
+        /// </summary>
+        public string Description { get; set; }
+
+        /// <summary>
+        /// Attributes
+        /// </summary>
+        public ICollection<RTagValue> Tags { get; set; }
+    }
+}
diff --git a/RMuseum/Models/PDFLibrary/MultiVolumePDFCollection.cs b/RMuseum/Models/PDFLibrary/MultiVolumePDFCollection.cs
index 7b2a7826..e46e7dff 100644
--- a/RMuseum/Models/PDFLibrary/MultiVolumePDFCollection.cs
+++ b/RMuseum/Models/PDFLibrary/MultiVolumePDFCollection.cs
@@ -11,9 +11,14 @@
         public int Id { get; set; }
 
         /// <summary>
-        /// Friendly Url
+        /// book id
         /// </summary>
-        public string FriendlyUrl { get; set; }
+        public int BookId { get; set; }
+
+        /// <summary>
+        /// book
+        /// </summary>
+        public Book Book { get; set; }
 
         /// <summary>
         /// Name
diff --git a/RMuseum/Models/PDFLibrary/PDFBook.cs b/RMuseum/Models/PDFLibrary/PDFBook.cs
index d8c380e7..f0cbab83 100644
--- a/RMuseum/Models/PDFLibrary/PDFBook.cs
+++ b/RMuseum/Models/PDFLibrary/PDFBook.cs
@@ -16,9 +16,14 @@ namespace RMuseum.Models.PDFLibrary
         public int Id { get; set; }
 
         /// <summary>
-        /// Friendly Url
+        /// book id
         /// </summary>
-        public string FriendlyUrl { get; set; }
+        public int BookId { get; set; }
+
+        /// <summary>
+        /// book
+        /// </summary>
+        public Book Book { get; set; }
 
         /// <summary>
         /// Publish Status
diff --git a/RMuseum/RMuseum.xml b/RMuseum/RMuseum.xml
index cf7baa71..5e25ba27 100644
--- a/RMuseum/RMuseum.xml
+++ b/RMuseum/RMuseum.xml
@@ -11583,6 +11583,61 @@
             <param name="dateTime"></param>
             <returns></returns>
         </member>
+        <member name="T:RMuseum.Models.PDFLibrary.Book">
+            <summary>
+            a book might have different PDFBook or MultiVolumePDFCollection instances
+            </summary>
+        </member>
+        <member name="P:RMuseum.Models.PDFLibrary.Book.Id">
+            <summary>
+            Id
+            </summary>
+        </member>
+        <member name="P:RMuseum.Models.PDFLibrary.Book.Name">
+            <summary>
+            book name
+            </summary>
+        </member>
+        <member name="P:RMuseum.Models.PDFLibrary.Book.Description">
+            <summary>
+            description
+            </summary>
+        </member>
+        <member name="P:RMuseum.Models.PDFLibrary.Book.Tags">
+            <summary>
+            Attributes
+            </summary>
+        </member>
+        <member name="T:RMuseum.Models.PDFLibrary.MultiVolumePDFCollection">
+            <summary>
+            Multi Volume Book
+            </summary>
+        </member>
+        <member name="P:RMuseum.Models.PDFLibrary.MultiVolumePDFCollection.Id">
+            <summary>
+            Id
+            </summary>
+        </member>
+        <member name="P:RMuseum.Models.PDFLibrary.MultiVolumePDFCollection.BookId">
+            <summary>
+            book id
+            </summary>
+        </member>
+        <member name="P:RMuseum.Models.PDFLibrary.MultiVolumePDFCollection.Book">
+            <summary>
+            book
+            </summary>
+        </member>
+        <member name="P:RMuseum.Models.PDFLibrary.MultiVolumePDFCollection.Name">
+            <summary>
+            Name
+            </summary>
+        </member>
+        <member name="P:RMuseum.Models.PDFLibrary.MultiVolumePDFCollection.Description">
+            <summary>
+            Description
+            </summary>
+        </member>
         <member name="T:RMuseum.Models.PDFLibrary.PDFBook">
             <summary>
             PDF Book
@@ -11593,9 +11648,14 @@
             Id
             </summary>
         </member>
-        <member name="P:RMuseum.Models.PDFLibrary.PDFBook.FriendlyUrl">
+        <member name="P:RMuseum.Models.PDFLibrary.PDFBook.BookId">
             <summary>
-            Friendly Url
+            book id
+            </summary>
+        </member>
+        <member name="P:RMuseum.Models.PDFLibrary.PDFBook.Book">
+            <summary>
+            book
             </summary>
         </member>
         <member name="P:RMuseum.Models.PDFLibrary.PDFBook.Status">
@@ -11673,6 +11733,21 @@
             claimed page count
             </summary>
         </member>
+        <member name="P:RMuseum.Models.PDFLibrary.PDFBook.MultiVolumePDFCollectionId">
+            <summary>
+            MultiVolumePDFCollection Id
+            </summary>
+        </member>
+        <member name="P:RMuseum.Models.PDFLibrary.PDFBook.MultiVolumePDFCollection">
+            <summary>
+            MultiVolumePDFCollection
+            </summary>
+        </member>
+        <member name="P:RMuseum.Models.PDFLibrary.PDFBook.VolumeOrder">
+            <summary>
+            Volume Order
+            </summary>
+        </member>
         <member name="P:RMuseum.Models.PDFLibrary.PDFBook.DateTime">
             <summary>
             Date/Time