This video is an introduction to the topic of dose reconstruction as it applies to the Energy Employees Occupational Illness Compensation Program Act. It is intended to provide our target audience (energy workers and their survivors) with a basic understanding of dose reconstruction and the dose reconstruction program. This introductory video is not intended to explain all of the complexities and nuisances within the science of dose reconstruction. After watching this video, we hope our audience has a better understanding of dose reconstruction and the dose reconstruction process, and recognizes that the NIOSH program is grounded in sound, scientific methods that give the benefit of the doubt to the worker whenever possible. We also hope that our audience considers the NIOSH staff to be friendly, knowledgeable, and approachable.