Prognostics and Health Management (PHM) is an emerging engineering discipline that enables real-time health assessment of a system as well as the prediction of its future state under its actual operating conditions. PHM has recently received great attention in various industries such as aerospace, smart manufacturing, power plants and transportation as a means to prevent failure, reduce operating cost and achieve predictive maintenance. It consists of several steps: sensors data acquisition, features extraction from the sensors data, anomaly detection, fault diagnosis to evaluate current health state, and failure prognosis to predict the remaining useful life. The PHM incorporates various disciplines including sensing technologies, physics of failure, machine learning, modern statistics, and reliability engineering, which means that PHM is broader than any single traditional field of engineering.