Dr Joshi has made important contributions in the areas of electronic states in disordered systems, electron correlation in narrow band solids and the related problem of Mott transition. He has proposed a number of models for the study of disordered materials; these models have been used to study the spectral functions and density of states for electrons in a number of binary alloys. He has also studied the problems of electrons in liquid metals and in amorphous semiconductors. He has studied excitation and ionization processes in atoms, ions and molecules due to impact of charged projectiles, such as electrons and protons. These collision processes are of interest in the study of plasma confinement, astrophysical problems and the upper atmosphere.