Open Questions in GRB Physics

Open questions in GRB physics are summarized as of 2011, including classification, progenitor, central engine, ejecta composition, energy dissipation and particle acceleration mechanism, radiation mechanism, long term engine activity, external shock afterglow physics, origin of high energy emission, and cosmological setting. Prospects of addressing some of these problems with the upcoming Chinese-French GRB mission, SVOM, are outlined.