About 13% of global electricity is derived from nuclear fission, and many new plants are under construction around the world. These tend to be very large, producing over a GW of electricity, costing billions, and taking many years to construct, piece-by-piece, on site. Popular opposition has led some nations to plan to discontinue their reliance on such facilities. There is also a large market, in principle, for small nuclear power plants, for remote communities, military bases, mines, and oilfields. Many firms are now developing Small Modular Reactors (SMR), which could be mass produced and shipped as sealed units, with high resistance to meltdown and proliferation concerns. The physics and engineering principles were demonstrated half a century ago, and modern methods indicate a bright future for SMR. This talk will emphasize the context and opportunities, but not the detailed designs, since the market is just opening.