This booklet gives an introduction to the issues raised by regulatory reform of the electricity sector. The sector is undergoing change worldwide. A key objective of reform is to improve efficiency in order to reduce prices for electricity consumers. More competitive power markets are required to achieve this objective, but security of supply must also be sustained in the new conditions, and environmental objectives are of growing importance. Ultimately, choices must be made by end-users themselves and not by others on their behalf. Hence, the structure of the industry needs to change to promote end-user choice, as do the regulatory institutions and rules that set the framework. The contents of this volume were first published as part of an OECD book on regulatory reform in a variety of sectors. This updated version of the study is one in a series of short publications by the IEA on energy market reforms.