A drupal theme is a collection of files that define the presentation layer. You can also create one or more "sub-themes" or variations on a drupal theme. Only the .info file is required, but most themes and sub-themes will use other files as well. The following diagram illustrates the files that are found in a typical drupal theme and sub-theme. Drupal 6: Drupal 7: .info (required) All that is required for Drupal to see your theme is a ".info" file. Should the theme require them, meta data, style sheets , JavaScripts , block regions and more can be defined here. Everything else is optional in drupal theme. The internal name of the theme is also derived from this file. For example, if it is named "drop.info", then Drupal will see the name of the theme as "drop". Drupal 5 and below used the name of the enclosing folder of the theme. Info files for themes are new in Drupal 6. In version 5, .info files were used solely for dru...