The solar thermal central receiver is a key component of any solar thermal plant. The efficiency with which a receiver accomplishes its function is of central interest in solar thermal technology. Solar thermal receivers have been built, evaluated, and operated in many countries. These experiences have provided a rich knowledge base on receiver performance and its evaluation. At the same time, the variety of methods and approaches used by different researchers has caused occasional difficulties in the interpretation of performance evaluation results reported in the literature. The rationale for this report, therefore, derives from two sources. First is the need to facilitate the evaluation of the performance of solar receivers by providing a central document defining standards for such endeavors; second, to enable an easy interpretation and comparative evaluation of different receiver concepts for which performance has been evaluated in different countries. The primary contribution of this report is deemed to be the definition of a minimum set of parameters essential for the evaluation of receiver performance, as well as the selection and recommendation of the methods that have proved to be the most successful for the measurement and calculation of these parameters. An extensive list of references is provided with each chapter.