For early history about Active Directory, you can't get much better than straight from the horse's mouth ( manager of the Exchange / Active Directory group ).

see https://hardcoresoftware.learningbyshipping.com/p/021-expand...

and

https://hardcoresoftware.learningbyshipping.com/p/bonus-the-...

I will say that in the era when they came out with AD they really took "enterprise configuration management" seriously and made Windows by far the best mainstream ecosystem to manage hundreds or thousands of corporate desktops.