There are two kinds of source documents available, single topic documents and multiple topic documents:

•      Single topic documents allow you to have only one topic per document. Only single-topic documents participate in the document tree hierarchy.

•      Multiple topic documents allow you to have as many topics as you would like. Word documents are always multiple topic documents, so there is no option for single topic Word documents. Although multiple topic documents are in the same tree as single topic documents, they always appear on the first level. Only single topic documents can be placed on deeper levels.

In this sample document tree, you will notice the single topic HTML source documents are placed on multiple levels, while the multiple topic Word documents only appear on the first level:

Unlike Word documents, HTML documents can be either single or multiple topic documents. You can specify which type you would like to use by selecting either the Single topic or Multiple topics radio button when you add or create a new HTML document in your project.

A multiple topic HTML document generates topics in the same way as Word documents generate topics. Topics are defined by their headings in the source document. Headings are formatted with paragraph styles that have the Style.Type property set to Level 1 through 9 in the Doc-To-Help project. The style level determines the level of the topic in the automatically generated table of contents (TOC). For example, the Style.Type property of the Heading 1 paragraph style is set to Level 1 in Doc-To-Help. If you apply the Heading 1 style to a topic in your source document, Doc-To-Help places the topic at Level 1 in the TOC.

A single topic HTML document directly corresponds to a topic in a help target. For a single topic document, you must specify the Title and Style of the topic, which can be done in the Adding HTML Documents or New HTML Document dialog box. This tells Doc-To-Help the title and position of the topic in the TOC hierarchy. The Style property directly corresponds with the paragraph styles in the project. If the Style property of a single topic document is set to Heading 1, the topic assumes all of the properties of the Heading 1 paragraph style. The document Style also corresponds to a level in the tree. This help you keep the document tree hierarchy synchronized with the TOC hierarchy. If the style does not correspond with the document's level in the tree when the document is added, Doc-To-Help gives you a warning and allows you to select another style. You are not required to match the document tree level and the Style level; this does not prevent the target from building correctly.

For your convenience, the Select Documents With Incorrect Style button  on the Documents toolbar can be used to check the entire tree for documents that do not have the same tree and TOC levels.

The document tree hierarchy usually follows the TOC hierarchy of the topics. The tree hierarchy does not necessarily follow the source documents directory structure, although you may find it convenient to store source documents in a directory hierarchy parallel to the document tree hierarchy.

Other than helping the user to organize single-topic documents in the same hierarchy as in the TOC, the document tree hierarchy does not play an essential role in creating help targets. The help target's TOC is created based solely on the Title and Style properties of the documents for single-topic documents and on the style formatting of topic headers in multiple topic documents.