While the development of computers with billion-transistor microprocessors has been evolutionary in the Moore’s law sense, it has been revolutionary in many other ways. Scaling to nanometer dimensions has blown the lid off our view of device physics based on drift and diffusion. Sophisticated simulations have shown that electron velocities in 22-nm MOSFET’s are 3X the so-called saturated velocity “limit”, and a new bottom-up understanding of ultra-scaled devices based on Landauer theory and quantum transport has been developed. Revolutionary advances in magnetic storage based on giant magnetoresistance and other newly discovered effects have also enabled today’s electronics, and this success has spurred interest in exploring electron spin for developing radically new ways of computing. As a result, a search for materials that could provide tailorable spin-dependent transport, such as graphene, transition-metal dichalcogenides and other 2D layered materials, has begun; and new approaches to nanoscale computing are being explored.