HelpNDoc - What is HelpNDoc ? Easy to use yet powerful help authoring environment which can generate various documentation formats from a single source.
Help & Manual - Help & Manual is a documentation authoring tool that allows you to create a single source text and convert it into a number of other target formats.
Dr.Explain - Dr.Explain software is a help file authoring tool.
CHM Editor - Best solution to edit CHM files
MadCap Flare - Documentation for Any Audience, Language or Format
Kchmviewer - Kchmviewer is a free, open-source CHM (MS HTML help) and EPUB viewer for Unix, Mac and Windows...