I'm not sure if you're aware of this, but when the Agile Manifesto was signed, a giant red button was pressed that reset the entire industry's memory.

All that existed before 2001 was waterfall. Nothing else. Just waterfall. Only waterfall. You are mistaken in thinking that iterative delivery, spiral models, joint application development, daily build-n-smoke, test harnesses or any such practice or technology existed previously.

Then in 2001, Agile sprung fully-formed from the brow of Zeus and saved us. Agile has no predecessors whatsoever and completely invalides decades of careful observation, discussion and investigation by generations of software developers and managers.

All books and articles published before 2001 can be safely ignored, and nothing can be learned therefrom.