  The interest of micro and tip-enhanced Raman spectroscopy to analyze
nanosized and nanostructured materials, chiefly semiconductors, oxides and
pristine or functionalized carbon nanotubes, is reviewed at the light of the
contributions to this special issue. Particular attention is paid to the fact
that chemical reactions, size or shape distribution, defects, strain and
couplings may add to nano-dimensionality in defining the Raman signature.
