Unfortunately book 2 is where the whole concept of the story became too smart for Asimov to write about, and it quickly devolves into bad pulp sci-fi.
SPOILER for book 5:
The """happy ending""" involves the protagonists leaving a traumatized child to be groomed by a robot so that when the kid grows up, the robot can wipe their mind, replace it with its own consciousness, and control humanity's destiny from the shadows. It's so disgusting and morally reprehensible...
Memorial toilets to do your patriotic duty