         delete @_savingTimeout
       ), SAVE_DELAY
 
-
+    # A book is not loaded until the navModel is loaded.
+    # Once the navModel is loaded, "autosave" whenever it changes.
     _loadComplex: (fetchPromise) ->
       fetchPromise
       .then () =>

          @_localNavAdded[model.id] = model


      @tocNodes.on 'tree:add',    (model, collection, options) => @tocNodes.add model, options
      @tocNodes.on 'tree:remove', (model, collection, options) => @tocNodes.remove model, options


      @on 'change:title', (model, value, options) =>
        $title = @$xml.find('title')
        if value != $title.text()
          $title.text(value)
          @_save()

      @tocNodes.on 'change:title', (model, value, options) =>
        return if not model.previousAttributes()['title'] # skip if we are parsing the file
        return if @ == model # Ignore if changing the OPF title

    branch: true # This element will show up in the sidebar listing

    initialize: () ->
      # For TocNode, let it know this is the root
      super {root:@}

      # Contains all entries in the OPF file (including images)
