To catch people up: I, Robot is a collection of short stories largely follow either (a) robopsychologist Susin Calvin or (b) robotics engineers Powell and Donovan as they attempt to diagnose anomalous behavior by examination of the 3 laws of robotics, highlighting the logical flaws and traps of these simple laws. A secondary theme is the use of robots as a mirror or lens through which particular human behaviors can be blown up and examined, largely through the absence or magnification of particular traits.
In universe, the 3 laws are considered to be practical engineering safeguards (and eventually, over hundreds of years, a fundamental building block to the function of the positronic brain)-- even as they are shown to the reader to be the origin of many conflicts.