The Three Laws of Robotics are:
1. A robot may not injure a human being or, through inaction, allow a human being to come to harm.
2. A robot must obey orders given to it by human beings, except where such orders would conflict with the First Law.
3. A robot must protect its own existence as long as such protection does not conflict with the First or Second Law.

These rules were written by ISAAC ASIMOV and were introduced in his story, "Runaround" in 1942. These rules must be obeyed by all the positronic robots in his stories.

Interesting question :)