Microsoft had great documentation in 1998. It is called MSDN VS 6.0. You can find it at WinWorldPC. You had everything there (in the documentation)! DirectX, WIN32API, what ever you wish... Hit F1 on random keyword and it would still pull out the documentation for it with code examples too. No need to connect to the internet.
Comparing that to nowadays Visual Studio documentation... it's... bad. Offline documentation has links to online resources which is missing the point. You have some information there but it is not complete, it is full of holes.
I did some kernel work a while back on a machine with no internet access. While I did use the internet on a laptop, it was mainly to read docs get help, so assuming I had all the docs offline, had the source already, and was smart enough with all the background knowledge (I seriously doubt lol), I suppose I could have done it offline.