[en] We have observed bulk solid superheating of the order of 650 K and persisting for Δt>500 ns in shocked single crystals of KBr at 22 to 33 GPa and CsBr at 30 to 42 GPa. These experiments use nanosecond-resolution, twelve-channel optical pyrometry to measure the temperature of the advancing shock front in the crystal, and the rarefaction-overtake technique to simultaneously measure sound velocity. This novel combination of measurements allows a virtually continuous determination of Hugoniot temperature versus pressure or density for transparent crystals