  Understanding how giant and terrestrial planets form and evolve, what is
their internal structure and that of their atmosphere, represents one of the
major challenges of modern astronomy, which is directly connected to the
ultimate search for life at the horizon 2040. However, several astrophysical,
biological and technological obstacles must be overcome. From the astrophysical
point of view, it is indeed crucial to understand the mechanisms of formation
and evolution of giant planets, including planet and disk interactions, which
will completely sculpt the planetary architectures and thus dominate the
formation of terrestrial planets, especially in regions around the host star
capable of supporting life. It is also important to develop dedicated
instrumentation and techniques to study in their totality the population of
giant and terrestrial planets, but also to reveal in the near future the first
biological clues of life in the atmospheres of terrestrial planets. In that
perspective, direct imaging from ground-based observatories or in space is
playing a central role in concert with other observing techniques. This review
introduces the genesis of this observing technique, the main instrumental
innovation and challenges, stellar targets and surveys, to then present the
main results obtained so far about the physics and the mechanisms of formation
and evolution of young giant planets and planetary system architectures. I will
then present the exciting perspectives offered by the upcoming generation of
planet imagers about to come online, particularly on the future extremely large
telescopes. On the timescale of a human Life, we may well be witnessing the
first discovery of an exoplanet and the first detection of indices of life in
the atmosphere of a nearby exo-Earth!
