Fixed a bug when opening a new book.

diff --git a/Librarian.lua b/Librarian.lua
index f0605cd..1f23c5e 100644
--- a/Librarian.lua
+++ b/Librarian.lua
@@ -95,7 +95,7 @@ function Librarian:AddLoreReaderUnreadToggle()
             alignment = KEYBIND_STRIP_ALIGN_RIGHT,
             name = function()
             	local book = self:FindBook(LORE_READER.titleText)
-            	if book.unread then
+            	if not book or book.unread then
             		if self.settings.showUnreadIndicatorInReader then
             			self.unreadIndicator:SetHidden(false)
             		else
@@ -110,6 +110,7 @@ function Librarian:AddLoreReaderUnreadToggle()
             keybind = "UI_SHORTCUT_SECONDARY",
             callback = function()
             	local book = self:FindBook(LORE_READER.titleText)
+            	if not book then return end
                 book.unread = not book.unread
                 KEYBIND_STRIP:UpdateKeybindButtonGroup(LORE_READER.keybindStripDescriptor)
                 self:RefreshData()