Famous three laws !

Clarke’s Three Laws (from the book "Profiles of the Future" by Arthur C. Clarke) [1]

1. “When a distinguished but elderly scientist states that something is possible, he is almost certainly right. When he states that something is impossible, he is very probably wrong.”
2. “The only way of discovering the limits of the possible is to venture a little way past them into the impossible.”
3. “Any sufficiently advanced technology is indistinguishable from magic.”

Asimov's Laws of Robotics [2]

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.

References
[1] NYT Article
[2] Wikipedia Article