A complete site-rip of a major Atari ST dev docs repository + extras from me.
http://dev-docs.atariforge.org/
For reading HYP files within an Atari ST:
EXTRAS...
--###SOFTWARE##--
- winguide.exe = Windows viewer for Atari HYPertext files (.HYP).
- Hatari & Steem = Atari ST emulators.
- ROMS = Use em with your emulators!!
- Everest = Atari ST text editor
- KnifeST = very excellent disk editor
- Mononomon = another disk editor. never used it
- TTD = TT Digger. Despite the name, works on ANY Atari ST. http://members.chello.nl/h.robbers/TTD.html
- ASSEMBLE & DEVPAC31 = assembly language compilers. Devpac31 was THE standard for Atari STs.
Devpac31 must sit in the Atari ST C drive root. To put it elsewhere, adjust the environment settings.
- PURE_C & LATTICE_C = C language compilers.
- INTRFACE = a resource editor. Can edit a program's GUI.
- SYSINFO.PRG = Gives you an overview of your Atari ST specs along with your Atari ST vectors (hdv_bpb, etc). If your technically savvy, you can spot memory resident viruses.

--###DOCUMENTS##--
- 68K references
- The ST Assembly Learning Workshop (ALW_V1 & ALW_V2). HYP format.
- Atari ST compendium. PDF & HTML
- Devpac3 manual. PDF & HYP (NOT easy to find!!!)
- ST_WORLD magazine articles (graphix coding). DJVU format.
I use WinDJVU. http://windjview.sourceforge.net/