This independent study course is intended to provide members of the general public with an overview of several types of radiological emergencies: radiological transportation accidents, nuclear power plant accidents, nuclear terrorism threat, and other radiological hazards. This overview introduces the nature, degree of hazard, and general emergency response strategies associated with each type of emergency. Specific emergency response guidance, such as how to operate radiation detection equipment or how to respond to a radiation incident, is presented in other courses. For optimal results, study this course carefully at your own pace. Learning from these materials is different than learning from a traditional textbook. The course is self-instructional and contains all of the information you need to increase your knowledge of radiological hazards. The course contains a pretest, five units, a final examination and a glossary. You should take the pretest to test your knowledge before you begin studying. You can score the pretest yourself, using the pretest answer key (located after the pretest questions), to determine units requiring additional emphasis. The glossary, located before the final exam, contains definitions of terms related to radiological hazards. The glossary may be consulted while you are reading the units or may be read separately.