DevComponents
- Makers of HelpKit, an HTMLHelp authoring tool, HTMLDocument, a class library for Visual Studio.Net that provides DOM (Document Object Model) for HTML documents, and HTML Help COM Assistant, which generates documentation for COM/ActiveX components and cont
- http://www.devcomponents.com/

HTML Helpy
- Shareware authoring tool designed for programmers and non-programmers. Includes testimonials and a demo version.
- http://www.mellowsoft.com/

KeyWorks Software
- Makers of KeyHelp, which provides native HTML popups, embedded windows, an auto-sizing secondary window, content-level information types, and various script extensions; KeyHH, which is a replacement for hh.exe you can use to make multiple calls that displ
- http://www.keyworks.net/

InnovaSYS
- Sells Visual Basic HTMLHelp tools to automate the production of context-sensitive help. Includes lists of features, evaluation versions, technical support, and ordering and pricing information.
- http://www.innovasys.co.uk/

Visual CHM
- WYSIWYG HTMLHelp editor you can use to create and decompile .CHM files. Includes a trial version, ordering and pricing information, FAQ, and a screenshot of the software.
- http://www.vchm.com

Theta-Software
- Products include HelpTron, a WYSIWYG environment for creating HTMLHelp, and HelpFiler, a tool for creating HTMLHelp contents and index files. Site includes trial versions, ordering and pricing information, and a bug report form.
- http://www.theta-software.com

Helpware
- Software tools for HTMLHelp developers, including FAR, which you can use to search and replace across multiple files and to edit your contents and index files. Also includes a FAQ, KnowledgeBase articles, forums, downloads, and books.
- http://www.helpware.net/

Virtual Media Technology
- Sells VMSuite, HDK, and HelpMate. Includes ordering and pricing information, trial versions, and technical support. [Windows]
- http://www.vmtech.com/