We summarize recent developments in the understanding of nuclear effects in
deep-inelastic lepton scattering. Our focus is on coherence phenomena, suc
h as shadowing, with special emphasis on the role of the nucleus as a diffr
active filter for hadronic and quark-gluon fluctuations of the high-energy
virtual photon. New results for the electroproduction of rho mesons from a
nucleus are discussed in the same context.