Contemporary research in science and engineering is seeking to harness the versatility and sustainability of living organisms.Living Machines: A handbook of research in biomimetic and biohybrid systems surveys this flourishing area of research, capturing the current state of play and pointing to the opportunities ahead. Promising areas in biomimetics include self-organization, biologically inspired active materials, self-assembly and self-repair, learning, memory, control architectures and self-regulation, locomotion in air, on land or in water, perception, cognition, control, and communication. Drawing on these advances the potential of biomimetics is revealed in devices that can harvest energy, grow or reproduce, and in animal-like robots that range from synthetic slime molds, to artificial fish, to humanoids.