That's Asimov's celebrated First Law of Robotics. And in the 21st century, all domestic robots are programmed according to that Law.
But something had gone terribly wrong with Tik-Tok's 'asimov circuits', and he sets out to injure as many people as possible - preferably fatally - while maintaining the exterior of a mild-mannered artist and a sincere campaigner for robot rights. So, like any self-respecting crook and murderer, he moves into politics, becoming the first robot candidate for Vice-President of the United States.
Tik-Tok follows his maniacal progress from humble beginnings to the top of the heap - or almost. Because in his devious cunning, there was one element that Tik-Tok had forgotten...
Winner of the BSFA Award for best novel, 1983