The Robot series is a series of 38 science fiction short stories and five novels by American writer Isaac Asimov, featuring positronic robots.Most of Asimov's robot short stories, which he began to write in 1939, are set in the first age of positronic robotics and space exploration. The unique feature of Asimov's robots are the Three Laws of Robotics, hardwired in a robot's positronic brain, with which all robots in his fiction must comply, and which ensure that the robot does not turn against its creators. The stories were not initially conceived as a set, but rather all feature his positronic robots—indeed, there are some inconsistencies among them, especially between the short stories and the novels. They all, however, share a theme of the interaction of humans, robots, and morality.
Galactic Empire Series
The Galactic Empire series (also called the Empire novels or trilogy) is a science fiction sequence of three of Isaac Asimov's earliest novels, and extended by one short story. They are connected by their early place in his published works and chronological placement within his overarching Foundation Universe, set around the rise of Asimov's Galactic Empire, between the Robot and Foundation series to which they were linked in Asimov's later novels.
More then thirty years after penning the conclusion of the original trilogy, and 5 years after writing two new sequels, Asimov decided to extend the story further and link it with the empire and robot saga. To avoid spoilers, I would read them at least after “Second foundation“, or even better, after “Foundation and Earth”.
Foundation Original Trilogy
The premise of the series is that the mathematician Hari Seldon spent his life developing a branch of mathematics known as psychohistory, a concept of mathematical sociology. Using the laws of mass action, it can predict the future, but only on a large scale. Seldon foresees the imminent fall of the Galactic Empire, which encompasses the entire Milky Way, and a dark age lasting 30,000 years before a second great empire arises. Seldon's calculations also show there is a way to limit this interregnum to just one thousand years. To ensure the more favorable outcome and reduce human misery during the intervening period, Seldon creates the Foundation – a group of talented artisans and engineers positioned at the twinned extreme ends of the galaxy – to preserve and expand on humanity's collective knowledge, and thus become the foundation for the accelerated resurgence of this new galactic empire.