A polished attorney suspected of being a robot during his campaign for mayor, Byerley becomes a significant figure in discussions about robots' potential role in governance. His unique behavior generates debate about his true nature.

Technicians who tackle various issues with robots in off-world assignments, often overcoming humorous predicaments during their endeavors. They appear regularly throughout the narrative, solving problems related to robotic behavior.

A mathematician and administrator at US Robots, Bogert often clashes with Dr. Calvin over robotics issues. His work involves mathematical solutions to robotics development challenges.

The head of US Robots, who frequently participates in key meetings, providing essential input on solving corporate problems. He contributes to the decisions made at the company, even with his impatient demeanor.

A young girl who adores her robotic nursemaid Robbie and demonstrates the emotional bond humans can have with robots. Her experiences highlight the impact of robots on personal lives.

A politician who accuses Stephen Byerley of being a robot to win a mayoral race, representing the opposition to robots in positions of authority. His actions underscore the political tensions involving robotics.

Various robots are featured throughout, each contending with the challenges and dilemmas posed by the Three Laws of Robotics. They highlight the intricate and sometimes problematic relationship between humans and robots.

An anti-robot group opposed to robotic integration into human society, especially in the Northern Region. They represent the broader societal resistance to technological advancement.