We have faced nuclear threats since 1945 with the advent of the atomic age. Today we have concerns about a range of threats related to nuclear technology. We will briefly review the basics of the nuclear story, keeping the lecture simple and concise. We will cover nuclear plant accidents, medical radiation abuse, the nuclear fuel cycle, “dirty” bombs, and international and “group” nuclear terrorism. The instructor will summarize what we are doing to prevent and minimize these risks and provide a look into the future.