A Spacer scientist from the planet Aurora, he specializes in creating robots which mimic the outward appearance of human beings—androids, although Asimov calls them "humaniform robots". His most significant creations are R. Daneel Olivaw and R. Jander Panell. R. Giskard Reventlov is another of his creations, though is not a humaniform robot, having a metal exterior. Fastolfe is Elijah Baley's chief Spacer ally; together, he and Baley are key figures in the human race's expansion into the Galaxy.