Daneel is introduced in The Caves of Steel, a serialized story published in Galaxy Science Fiction from October to December 1953.

[3] He can convincingly mimic human behavior and reactions, is better able to adapt and evolve through increased knowledge and experience, and can perform "cerebroanalysis", an ability defined as an "interpretation of the electromagnetic fields of living brain cells" that provides "information of the temperamental and emotional makeup of an individual.

"[1] Asimov's concept of cerebroanalysis in 1953 predicted magnetic resonance imaging (first demonstrated in 1973), and also its later (and currently debated) use to determine truthfulness or deceit.

Along with the murder mystery aspect, the stories focus on discussions regarding space exploration and human societal norms, and show an evolution in both the friendship developing between the two characters and Daneel's personal sense of morality.

[8][9][10][11] Daneel is a robot built by Roj Nemennuh Sarton and Han Fastolfe, who are Spacer roboticists from the planet Aurora, in the year 4920 AD.

Daneel has a broad, high-cheekboned face and short bronze hair lying flatly backward and without a parting.

He wears clothes and, in The Caves of Steel, cannot be told apart from a human unless in a situation where he refuses to violate the Three Laws of Robotics, and even in this case is indistinguishable from a particularly altruistic person.

In The Caves of Steel, Daneel reveals that he has the capability to perform cerebroanalysis enabling him to interpret the emotional makeup of human brain activity.

Daneel is introduced in the book The Caves of Steel, where he is tasked to assist Elijah Baley in the investigation of the murder of his creator, Roj Nemennuh Sarton.

Daneel learns from Baley's methods of investigation in both books, which leads to him playing a larger role in The Naked Sun.

The murder victim is a humanoid robot, R. Jander Panell, who belonged to Gladia Delmarre and is physically similar to Daneel.

Unknown to the public, Gladia and Jander had a sexual relationship and she secretly regarded the humanoid robot as her husband.

When asked about the now mythic figure of Baley (whose existence is now questioned), Daneel states that he was greater than any myth claimed him to be.

Hari Seldon's wife Dors Venabili is the only one of Daneel's humanoid robot allies to be shown in the books.

As Hummin, he convinces Seldon that Cleon's first minister Eto Demerzel is pursuing him and that it is imperative for Hari to escape and to try making psychohistory practical.