The basic logic is very simple. Countries around the globe have a need for more electrical generating capacity because of increases in population and increases in energy use per capita. The needs are constrained by the requirement that the ba- load energy source be economical, secure, and not emit climate-changing gases. Nuclear power fits this description. Therefore, many countries that have not had a nuclear power program (or only had a small program) see a need to develop one in the future. However, the development of a national nuclear energy program is not so simple. The purpose of the NATO Advanced Research Workshop on Nuclear Power and Energy Security was to contribute to our understanding of how these programs might evolve. The workshop took place 26-29 May 2009 in Yerevan, Armenia. Approximately 50 participants discussed the infrastructure that is needed and some of the reactor options that might be considered. The papers in this book helped define the discussion that took place. The infrastructure that is needed includes a legal framework, a functioning regulator, a plan for waste disposal, a plan for emergency response, etc. These needs were explained and just as importantly, it was explained what international, bilateral, and regional cooperation is available. Although there were many co- tries represented, the Armenian experience was of particular interest because of where the meeting was located. The papers on reactor options covered both innovative and evolutionary designs.