  As astronomers, we are living an exciting time for what concerns the search
for other worlds. Recent discoveries have already deeply impacted our vision of
planetary formation and architectures. Future bio-signature discoveries will
probably deeply impact our scientific and philosophical understanding of life
formation and evolution. In that unique perspective, the role of observation is
crucial to extend our understanding of the formation and physics of giant
planets shaping planetary systems. With the development of high contrast
imaging techniques and instruments over more than two decades, vast efforts
have been devoted to detect and characterize lighter, cooler and closer
companions to nearby stars, and ultimately image new planetary systems.
Complementary to other planet-hunting techniques, this approach has opened a
new astrophysical window to study the physical properties and the formation
mechanisms of brown dwarfs and planets. I will briefly review the different
observing techniques and strategies used, the main samples of targeted stars,
the key discoveries and surveys, to finally address the main results obtained
so far about the physics and the mechanisms of formation and evolution of young
giant planets and planetary system architectures.
