Delivering help information in a consistent manner on Windows computers was an important concern for Microsoft. Initially, Microsoft provided the WinHelp format for help content delivery. As the Windows platform advanced, Microsoft introduced the Microsoft HTML Help format. To help authors deliver content through the HTML Help Viewer provided with the Windows platform, Microsoft provides a help compiler and toolkit, HTML Help Workshop, that allows you to build Microsoft HTML Help .chm files.

The Microsoft HTML Help output format provides a standard help format for products on computers running the Windows operating system. The Microsoft HTML Help format delivers a single, compiled file that includes multiple source files compressed into one .chm file. Unlike the RTF-based Microsoft WinHelp format, the Microsoft HTML Help format is based on HTML/XHTML. Microsoft HTML Help is recommended to produce online help for 32-bit applications that run on a computer running Microsoft Windows 95 or later, including Windows Vista:

Microsoft HTML Help provides a comprehensive help format, including a table of contents, index, full-text search, and favorites in one integrated viewer window. The HTML Help Viewer uses standard Internet Explorer components and supports many Web technologies, such as HTML, ActiveX, Java, JavaScript, JScript and other scripting languages, and the Web image formats, such as .gif, .jpg, and .png.

In HTML Help, writers list a collection of source files in a help project .hhp file with other project-related settings. The writers then use HTML Help Workshop to compile the help and create the .chm file. During compilation, HTML Help Workshop uses the help project .hhp file to determine how HTML topic files, image files, contents .hhc files, index .hhk files, and any other elements appear in the single, compressed help file. ePublisher automates this process and integrates it into help generation.