Progress in Energy and Combustion Science (PECS) publishes review articles on all aspects of energy and combustion science, providing a comprehensive in-depth overview of a particular topic. Occasionally, PECS solicits short Perspectives to highlight recent successes, current developments, and future research needs in energy and combustion science. While PECS spans the broad field of energy science, it focuses particularly on the fields of combustion and fuel science. Combustion has played an important role in the world's energy systems and will continue to do so in years to come. As time passes, technological demands evolve and change. For instance, the challenges we face today include conservation of energy, addressing the problem of global climate change, and environmental concerns, and together these require more efficient and cleaner combustion. Beyond energy, combustion plays an important role in process technology and materials science. PECS publishes reviews on all such topics, including concepts, methodologies, processes, and technology.