<p>Frontal polymerization (FP) is an exothermic polymerization process in which the reaction propagates as a self-sustaining wave-like front, powered by locally generated heat. FP has emerged as a reliable strategy for converting monomers into polymers, with minimal external energy input limited to the initial triggering of the reaction. FP is characterized by high polymerization rates and conversions within a short reaction time. It has been successfully used for synthesizing thermoplastic and thermosetting bulk polymers, thin films and (macro-to-nano) composites with interesting properties. In this Primer, we introduce the basic concepts of FP, explaining the general mechanisms, the suitable monomers and initiators, and the experimental factors affecting the overall FP processes. We then provide the reader with a troubleshooting section to avoid most of the common mistakes made by early stage scholars who are not familiar with FP experiments. Finally, we cover applications, future trends and emerging FP strategies designed to expand current capabilities and overcome limitations.</p>