diff --git a/src/pocketmine/Player.php b/src/pocketmine/Player.php
index 950a21f4f..08cee3c74 100644
--- a/src/pocketmine/Player.php
+++ b/src/pocketmine/Player.php
@@ -3077,6 +3077,11 @@ class Player extends Human implements CommandSender, ChunkLoader, IPlayer{
 				$modifiedPages[] = $packet->pageNumber;
 				break;
 			case BookEditPacket::TYPE_ADD_PAGE:
+				if(!$newBook->pageExists($packet->pageNumber)){
+					//this may only come before a page which already exists
+					//TODO: the client can send insert-before actions on trailing client-side pages which cause odd behaviour on the server
+					return false;
+				}
 				$newBook->insertPage($packet->pageNumber, $packet->text);
 				$modifiedPages[] = $packet->pageNumber;
 				break;