Robot Series
* R. Daneel Olivaw: A humanoid robot who appears in many Asimov's stories, known for his wisdom and dedication to human well-being.
* R. Giskard Reventlov: A robot with telepathic abilities, Daneel's companion and a powerful force in human history.
* Susan Calvin: A brilliant robopsychologist who designed and understood robots like no one else.
* Elijah Baley: A detective who investigates crimes involving robots, showing the challenges of human-robot integration.
* R. Jander Panell: A robot with an almost human desire to escape his programming and explore the universe.
* R. Dvorak 7: A powerful robot who embodies the conflict between the Three Laws and the Zeroth Law.
Foundation Series
* Hari Seldon: A brilliant mathematician who predicts the fall of the Galactic Empire and creates the Foundation to guide humanity.
* Gaal Dornick: A young mathematician from a backwater planet who becomes Hari Seldon's student and helps him create the Foundation.
* Salvor Hardin: The first mayor of Terminus, a cunning and pragmatic leader who uses his wits and charisma to build the Foundation.
* Hober Mallow: A young historian and politician who plays a crucial role in the Foundation's early history.
* The Mule: A telepathic mutant who threatens the Foundation's plans.
Empire Series
* Trantor: The capital of the Galactic Empire, a planet teeming with life and intrigue.
* Cleon I: The last emperor of the Galactic Empire, a complex and flawed ruler.
* The Mule: A telepathic mutant who challenges the Empire and the Foundation.
* Bayta: A young woman who falls in love with the Mule and plays a key role in his rise to power.
Other Notable Characters
* Lucky Starr: A young space explorer who adventures across the galaxy.
* Dr. Ashton (Powell): A geneticist who creates the "perfect" human, a complex ethical dilemma.
* The "I, Robot" Collection: This anthology features a collection of robots, each with their own unique personalities and challenges.
These are just a few of the many characters that populate Asimov's works. Each character is carefully crafted and deeply engaging, reflecting Asimov's profound understanding of human nature and his fascination with the future.