Springer International Publishing AG, part of Springer Nature 2018. All rights reserved. Phase change materials (PCMs) primarily leverage latent heat during phase transformation processes to minimize material usage for thermal energy storage (TES) or thermal management applications (TMA). PCMs effectively serve as thermal capacitors that help to mitigate the imbalance between energy demand and supply, to address the inherently transient nature of applications that require TES or TMA. PCMs provide higher energy storage density, since latent heat values are significantly higher than sensible heat. PCMs can enable the realization of isothermal reservoirs which serve as a heat source or heat sink. Reliability of PCM for TES or TMA is typically tested by their ability to withstand multiple charging and discharging cycles. In numerous literature reports, PCMs were explored for TES or TMA - ranging from solar power harvesting to thermal management of buildings. The wide range of information on PCMs are culled from the literature reports and summarized in this study. The culled information is categorized into history of PCMs, types (organic/inorganic), analytical formulations (for charging/discharging cycles), protocols for thermophysical property measurements (microscale/macroscale), reliability issues, applications, and identification of future research directions.