Artificial life, or A-life, studies artificial systems that mimic natural living systems through computer simulation, robotics, and synthetic biology. It aims to understand the general principles of life in any context. Key areas of A-life research include software-based simulations using cellular automata and neural networks, hardware-based robotics, and biochemical simulations of synthetic DNA. Open problems in A-life include understanding the origin of life and the potentials and limits of living systems.