  Ion acceleration driven by superintense laser pulses is attracting an
impressive and steadily increasing effort. Motivations can be found in the
potential for a number of foreseen applications and in the perspective to
investigate novel regimes as far as available laser intensities will be
increasing. Experiments have demonstrated in a wide range of laser and target
parameters the generation of multi-MeV proton and ion beams with unique
properties such as ultrashort duration, high brilliance and low emittance. In
this paper we give an overview of the state-of-the art of ion acceleration by
laser pulses as well as an outlook on its future development and perspectives.
We describe the main features observed in the experiments, the observed scaling
with laser and plasma parameters and the main models used both to interpret
experimental data and to suggest new research directions.
