All living creatures interact with their environment: even the most basic have a set of innate motor circuits they rely on to feed, locomote, fight, and flee. In , Sten Grillner describes the evolution of the motor repertoire of vertebrates, from protovertebrates to primates. With breadth and depth, Grillner explores how the brain uses the different microcircuits in the brainstem and spinal cord, coordinating them through commands from the forebrain. He also considers the normal function of the brain as a platform for understanding clinical conditions such as stroke, Parkinson´s and Huntington´s diseases, and spinal cord injury. Grillner also explains in how the remarkable finding that the lamprey forebrain has all the components of the mammalian one has radically changed scientists’ views on the evolutionary origin of the vertebrate forebrain. We now know that the basic organization evolved 560 rather than 300 million years ago, as was previously thought. The forebrain, says Grillner, is like an orchestra conductor, while the microcircuits, with their reaching, grasping, posture, locomotion, and numerous other patterns of behavior, correspond to the members of the orchestra. The conductor determines when each will be called into action. Providing an elegantly integrated perspective, is essential reading for anybody that works professionally with movement control and function and dysfunction, whether in basic research, clinically, or in the training of motor skills.