Looking for info on MS Help Viewer 1.0 (formally Help 3)... you came to the right place.
Rob Chandler is an MS Help MVP and runs The Helpware Group web site which contains lots of helpful info on MS Help technology.
It's been many years since we had a new help system so I'm very excited about MS Help Viewer. The API is way beyond anything we have had in the past (a developers dream). Have a look at the H3Viewer.exe app which was done in just a few days using Delphi. This help system has the potential to become the next general help system (not just for VS Help).