We introduce fundamental concepts of swarm robotics and provide a little overview. Swarm robotics is a complex approach that requires an understanding of how to define swarm behavior, whether there is a minimum size of swarms, and what the requirements and properties of swarm systems are. We define self-organization and develop an understanding of feedback systems. Swarms do not necessarily need to be homogeneous but can consist of different types of robots, making them heterogeneous. We also discussed the interaction of robot swarms with human beings as a factor.