This book provides an overview of the techniques offered to regulators of recently 'privatized' utilities and transport services. Designed as a starter kit, the book not only surveys the options available, but also provides guidelines as to how to chose between these options, identifying the costs and benefits of the various approaches in situations most relevant to regulators. It covers the measurement of efficiency in the context of a tariff revision aiming at redistributing at least some of the efficiency gains from the producers to the users. The book also addresses the challenges from comparative efficiency assessments allowing the introduction of yardstick competition. The book is intended to be self-contained for regulators who need to actually focus on the measurement of the efficiency of the firms they are monitoring.