We present manifestations of many-electron effects in photoionization, fast electron scattering and vacancy decay in atoms and multi-atomic formations. We will describe powerful collective effects in isolated atoms, namely giant resonances, interference and intra-doublet resonances and strong modification of the vacancy decay rate, e.g. radiative self locking of atomic shells. Similar resonances manifest themselves in molecules, clusters, fullerenes and endohedrals - normal atoms caged by a fullerene's shell.

Resonances and collective effects in atomic electron shells are modified due to action of strongly collectivized multi-electron shell of the fullerenes, leading to new families of resonances - confinement, giant endohedral and inter-shell. Giant endohedral resonances exceed the biggest atomic Giant resonance by two orders of magnitude. Fullerene's shells also modify profoundly the vacancy decay probabilities and open new decay channels amplifying the decay rate up to five orders of magnitude. Attention will be given to two- and multi-shell fullerenes.

Most of the results presented are obtained in using Random Phase Approximation with Exchange, accurate for atoms and simplified for fullerenes.