The resurgence of the nuclear power industry at a time when the nuclear plant I and C workforce is diminishing due to aging and retirements has been the motivation for writing this book. This book compiles 30 years of practical knowledge gained by the author and his staff in testing the I and C systems of nuclear power plants around the world. It focuses on process temperature and pressure sensors and the verification of these sensors calibration and response time. In spite of great advances in electronics, computers, and measurement technologies, important process parameters such as temperature and pressure are still measured with conventional sensing techniques found in RTDs, thermocouples, and conventional pressure and differential pressure sensors. Furthermore, no improved technology providing comparable performance is currently on the horizon. Therefore, it is important to understand how these sensors function and the testing techniques for verifying their performance. This book is intended to help provide this understanding.