[1] The Visual Studio SDKs for 2005 and 2008 include older CTP versions of Sandcastle,[2] although the latest release is available on GitHub.
These two different types of HTML output share the same presentation style and may be compiled together to produce mixed user/reference documentation.
Sandcastle provides a conceptual build component stack (conceptual.config) that resolves shared content and links, and uses XSL files to transform MAML elements into HTML.
A "doc model" XSL transformation, provided by the chosen presentation style, is applied to define the files that will be generated.
For example, the typical Help 1.x build process starts by running MrefBuilder.exe to produce an XML reflection file for one or more assemblies.
The reflection file is then processed by the XslTransform.exe tool multiple times to apply various XSL transformations that add data such as a "doc model" and optional version information.
Microsoft released Sandcastle as a Community Technology Preview (CTP) version in July 2006, a few days before NDoc was declared dead [3][4] The author of NDoc, Kevin Downs, cited in an email sent through his mailing list reasons for discontinuing development of his popular tool as a lack of community support, both financially and as development contributions, an automated mail-bomb attack on his public email address and the NDoc2 mailing list address, and also his impression that Sandcastle "will become the de facto standard and that NDoc will slowly become a stagnant side-water."