# Working with DTDs

This sections contains information on the following:

- Creating DTDs
  A document type definition (DTD) contains a set of rules that can be used to validate an XML file. After you have created a DTD, you can edit it manually, adding declarations that define elements, attributes, entities, and notations, and how they can be used for any XML files that reference the DTD file.
- Importing DTDs
  If you want to work with DTD files that you created outside of the product, you can import them into the workbench and open them in the DTD editor.
- Validating DTDs
  Validating a DTD file lets you verify that it is well formed and does not contain any errors.
- Icons used in the DTD editor
  These DTD editor icons appear in the Outline view.
- DTD editor keyboard shortcuts