  $\alpha$-clustering study since the pioneering discovery of $^{12}$C+$^{12}$C
molecular resonances half a century ago. Our knowledge on physics of nuclear
molecules has increased considerably and nuclear clustering remains one of the
most fruitful domains of nuclear physics, facing some of the greatest
challenges and opportunities in the years ahead. The occurrence of "exotic"
shapes in light $N$=$Z$ $\alpha$-like nuclei is investigated. Various
approaches of the superdeformed and hyperdeformed bands associated with
quasimolecular resonant structures are presented. Evolution of clustering from
stability to the drip-lines is examined: clustering aspects are, in particular,
discussed for light exotic nuclei with large neutron excess such as
neutron-rich Oxygen isotopes with their complete spectrocopy.
