The emission of electrons from solid surfaces bombarded by slow neutral and ionized heavy particles (atoms, molecules) is reviewed both theoretically and in the light of recent experimental studies by leading groups in the field: Kinetic emission from grazing incidence of atoms and kinetic and potential emission from grazing incidence of singly and multiply charged ions on monocrystalline metal and insulator surfaces; modelling of slow electron transport in solids; emission of spin-polarized electrons by ion neutralization; electron emission from slow ion induced plasmons and excitons.