Professor Atrey delivered 42 online video lectures for the course Cryogenic Engineering through NPTEL (National Programme on Technology Enhanced Learning). This course assumes that the students have undergone UG courses in Engineering Mathematics, Thermodynamics, Heat Transfer and Refrigeration. The purpose of this course is to give introductory knowledge of Cryogenic Engineering. The course also gives detailed knowledge of cryocoolers, on which research is going on world wide. The treatment is both theoretical and mathematical. The course will interest students wishing to embark on a research career in Cryogenic Engineering.