**3. Theories of GRB Prompt Emission**

Several current models can successfully interpret some of the spectral and temporal features of GRB emission. The main unknowns in the models for prompt emission are the nature of the energy reservoir and the subsequent energy dissipation, details of the particle acceleration mechanism, and the dominant radiative process. Within current leading models, the observed non-thermal spectrum is interpreted as either [i] a synchrotron and synchrotron self-Compton radiation from a population of relativistic electrons accelerated during the energy dissipation in the outflow (e.g., [79,80]), or [ii] as a Comptonized quasithermal emission from the photosphere (e.g., [81–84]). We give an overview and outline the main problems for the several leading models.
