diff --git a/Emby.Server.Implementations/Library/Resolvers/Books/BookResolver.cs b/Emby.Server.Implementations/Library/Resolvers/Books/BookResolver.cs
index 0b93ebeb8..503de0b4e 100644
--- a/Emby.Server.Implementations/Library/Resolvers/Books/BookResolver.cs
+++ b/Emby.Server.Implementations/Library/Resolvers/Books/BookResolver.cs
@@ -11,7 +11,7 @@ namespace Emby.Server.Implementations.Library.Resolvers.Books
 {
     public class BookResolver : MediaBrowser.Controller.Resolvers.ItemResolver<Book>
     {
-        private readonly string[] _validExtensions = { ".pdf", ".epub", ".mobi", ".cbr", ".cbz", ".azw3" };
+        private readonly string[] _validExtensions = { ".azw", ".azw3", ".cb7", ".cbr", ".cbt", ".cbz", ".epub", ".mobi", ".opf", ".pdf" };
 
         protected override Book Resolve(ItemResolveArgs args)
         {
diff --git a/MediaBrowser.Model/Net/MimeTypes.cs b/MediaBrowser.Model/Net/MimeTypes.cs
index fe2fbe7e4..b491a015c 100644
--- a/MediaBrowser.Model/Net/MimeTypes.cs
+++ b/MediaBrowser.Model/Net/MimeTypes.cs
@@ -67,6 +67,7 @@ namespace MediaBrowser.Model.Net
             { ".m3u8", "application/x-mpegURL" },
             { ".map", "application/x-javascript" },
             { ".mobi", "application/x-mobipocket-ebook" },
+            { ".opf", "application/oebps-package+xml" },
             { ".pdf", "application/pdf" },
             { ".rar", "application/vnd.rar" },
             { ".srt", "application/x-subrip" },