# File lib/chef/cookbook_loader.rb, line 147
    def [](cookbook)
      if @cookbooks_by_name.has_key?(cookbook.to_sym)
        @cookbooks_by_name[cookbook.to_sym]
      else
        raise ArgumentError, "Cannot find a cookbook named #{cookbook.to_s}; did you forget to add metadata to a cookbook? (http://wiki.opscode.com/display/chef/Metadata)"
      end
    end