Although crystalline silicon PV technology has been in use for more than 30 years, PV has remained a "cottage industry" until the recent expansion. This paper provides an introduction to the issues of reliability in the photovoltaic (PV) field, and the work the Department of Energy's Solar Energy Technologies Program is focused on to address these issues. In particular, the works of the Reliability Programs at both Sandia National Laboratories and the National Renewable Energy Laboratory are reviewed with several examples of results included and sited. Expanding reliability assessment and failure analysis techniques for components and systems can enhance the reliability of PV systems, which is necessary for large-scale deployment of PV as a power generation source.