Cognitive enhancement technologies raised hope in boosting healthy brain functioning, increasing mental capacity, speed, and creativity, through use of electrical and magnetic currents. How do these technologies work? How is the brain affected? And what are the ethical and societal implications of their use? Professor Roi Cohen Kadosh, Professor of Cognitive Neuroscience at the University of Oxford, and Dr Hannah Maslen, Postdoctoral Research Fellow in Ethics at the University of Oxford, examine what happens when we combine mind and machine.