Donavan Hall is maintaining the AlphaDocumentation site where lots of great documentation resides:
Personal Note: I suppose that I have dropped off the edge of the world. I've not forgotten Alpha or its documentation. Five months ago I switched careers and have been distracted with the mundanities of life. I don't know how I would do my work without Alpha. Now Alpha is more important to me than ever. Long live Alpha. (1 March 2003)
Mail Mode Ideas
An Introduction to Authoring Systems
Covers all aspects of authoring documents using a Macintosh. Text processing with Alpha; typesetting with Tex; BibTeX; Excalibur; content databases; scripting for authors.
Typesetting for Physicists: Using RevTeX and TeXsis
Provides comprehensive documentation for these two TeX macro packages. Include a chapter on "How TeX Works" and another on using these packages to generate PDF files.