The best description of the development of Windows NT, in my opinion,
is the book "Showstopper!: The Breakneck Race to Create Windows NT and
the Next Generation at Microsoft" by G. Pascal Zachary:
https://www.amazon.com/Showstopper-Breakneck-Windows-Generation-Microsoft/d…
Although Amazon gives it a 2014 publication date it is much older.
Well worth reading.
Arnold