Authoring

The Microsoft HTML Help 1.3 SDK is the official way to create CHM's. The HTML Help Compiler (HHC) takes a HTML Help Project (HHP) file with metadata, a HTML Help Contents (HHC) with the table of contents, and a HTML Help Index (HHK) with the index keywords, and the HTML pages, producing a CHM.

HTML Help Maker is an open-source project which plans to allow the creation of CHM's

Many open-source tools automatically generate the HHP, HHC, and HHK together with the HTML output. Especially worth noting are:

• DocBook XSL Stylesheets
• Doxygen
• texi2html

Format

Microsoft never released the format specification, but there are a few reverse engineered descriptions of the format:

• Unofficial CHM Specification
• Matthew Russotto's Microsoft's HTML Help format description

There are some tools which allow to read the contents of CHM files:

• CHMLIB
• libmspack — a library for Microsoft compression formats

Viewers

• Microsoft HTML Help Viewer
• xCHM — a CHM viewer for UNIX (Linux, BSD, Solaris), written by Razvan Cojocaru
• JouleData Solutions' CHM Viewer — a comercial 100% native Cocoa .chm file viewer for the Mac OS X platform
• GnoCHM — a CHM file viewer. It is designed to integrate nicely with Gnome.
• chmviewer
• ChmSee
• Chmox — a Mac OS X CHM viewer
• KchmViewer — a Qt/KDE based viewer of CHM files

Links

• HTML Help (CHM) Tools and Information
• Helpware