Some authors create multiple Help systems and distribute them as a group. This is useful if your project is large and you want to organize it by categories (for example, by modules in your application). With merged .CHM files, the main point of entry is through the Contents and/or Index tabs.
You can combine the contents files from the multiple .CHM files into the master .CHM (the file that provides the main point of entry to all other files and topics). You do this by setting up the table of contents in the master project to include external contents files (.HHC) used in the secondary Help files.
It is not necessary to include books and pages in the master .CHM file. However, the table of contents in this file should include one book at the top level containing all the external table of contents references. When users open this book, it expands to show the book icons for the other contents files.
You can customize your table of contents. For example, if you assign custom book and page icons to any of the books or pages in any of the external tables of contents, these icons will be displayed from the Contents tab in the HTML Help viewer. When users select a page, the topic that references it opens in the right-hand pane.
Tips for using external contents files with master projects:
This process involves the following steps: