Contents: Summary of NRL accelerator development Interior ballistics of hypervelocity projectors instrumented light gas gun and traveling charge gun Experiments with a two million volt electrostatic accelerator Studies of hypervelocity impact of metals Some theoretical models of hypervelocity Inertial, viscous and plastic effects in high speed impact A theoretical study of dynamic plastic deforma tion under impact loads Hydrodynamics applied to hypervelocity impact Penetration by hypervelocity particles A model of non-explosive impact Application of hydrodynamic theory to the low stress range of hypervelocity impact problems Visco-plastic flow theory in hypervelocity perforation of plates.