To create a master document, you start with an outline and then designate headings in the outline as subdocuments. You can also add an existing document to a master document to make it a subdocument.

A master document allows you to create a table of contents, index, cross-references, and headers and footers (header and footer: A header, which can consist of text or graphics, appears at the top of every page in a section. A footer appears at the bottom of every page. Headers and footers often contain page numbers, chapter titles, dates, and author names.) for all of the subdocuments.

You can use outline view (outline view: A view that shows the headings of a document indented to represent their level in the document's structure. You can also use outline view to work with master documents.) to work in a master document. For example, you can:

• Expand or collapse subdocuments or change views to show or hide detail.

• Quickly change the structure of the document by adding, removing, combining, splitting, renaming, and rearranging subdocuments.

To work with the contents of a subdocument, open it from the master document. When subdocuments are collapsed in the master document, each subdocument appears as a hyperlink (hyperlink: Colored and underlined text or a graphic that you click to go to a file, a location in a file, a Web page on the World Wide Web, or a Web page on an intranet. Hyperlinks can also go to newsgroups and to Gopher, Telnet, and FTP sites.). When you click the hyperlink, Microsoft Word displays the subdocument in a separate document window.

The template (template: A file or files that contain the structure and tools for shaping such elements as the style and page layout of finished files. For example, Word templates can shape a single document, and FrontPage templates can shape an entire Web site.) you use for a master document controls the styles (style: A combination of formatting characteristics, such as font, font size, and indentation, that you name and store as a set. When you apply a style, all of the formatting instructions in that style are applied at one time.) used when you view and print the entire document. You can also use different templates — or use different settings within the templates — for the master document and for individual subdocuments.

If someone is currently working on a subdocument, the document is "locked" to you and others. This means that you can view the subdocument, but you can't modify it until the other person closes the subdocument.

If you want to prevent unauthorized users from viewing or changing a master document or subdocument, you can open the document and assign a password to limit access to the document. You can also set an option to open the file as read-only (read-only: A setting that allows a file to be read or copied, but not changed or saved. If you change a read-only file, you can save your changes only if you give the document a new name.). (Note that if you set file sharing to the read-only option, the subdocument is "locked" to other users.)