In this book, advanced methods and techniques of monitoring, fault diagnostics, and predictive maintenance for cryogenics are illustrated. In Part I on Background, mainstreams in the related research are reviewed. In Part II of Methods, for monitoring helium distribution and consumption in cryogenic systems for particle accelerators, a virtual flowmeter is presented. Then, for fault diagnostics, two methods, for fault detection on a compressor, and for distributed diagnostics based on a micro-genetic algorithm, are described. Finally, for predictive maintenance, a metaheuristic optimization scheduling algorithm is illustrated. In Part III of Application examples, several practical case studies are described for highlighting the application of the previous methods to cryogenics of particle accelerators at CERN.