Heat exchangers are key components of most power conversion systems, a few industrial sectors can particularly benefit from high temperature heat exchangers. Examples include conventional aerospace applications, advanced nuclear power generation systems, and high efficiency stationary and mobile modular fossil fuel to shaft power/electricity conversion systems. This paper provides a review of high temperature heat exchangers in terms of build materials, general design, manufacturing techniques, and operating parameters for the selected applications. Challenges associated with conventional and advanced fabrication technologies of high temperature heat exchangers are discussed. Finally, the paper outlines future research needs of high temperature heat exchangers.