  The direct images of giant extrasolar planets recently obtained around
several main sequence stars represent a major step in the study of planetary
systems. These high-dynamic range images are among the most striking results
obtained by the current generation of high angular resolution instruments,
which will be superseded by a new generation of instruments in the coming
years. It is therefore an appropriate time to review the contributions of high
angular resolution visible/infrared techniques to the rapidly growing field of
extrasolar planetary science. During the last 20 years, the advent of the
Hubble Space Telescope, of adaptive optics on 4- to 10-m class ground-based
telescopes, and of long-baseline infrared stellar interferometry has opened a
new viewpoint on the formation and evolution of planetary systems. By spatially
resolving the optically thick circumstellar discs of gas and dust where planets
are forming, these instruments have considerably improved our models of early
circumstellar environments and have thereby provided new constraints on planet
formation theories. High angular resolution techniques are also directly
tracing the mechanisms governing the early evolution of planetary embryos and
the dispersal of optically thick material around young stars. Finally, mature
planetary systems are being studied with an unprecedented accuracy thanks to
single-pupil imaging and interferometry, precisely locating dust populations
and putting into light a whole new family of long-period giant extrasolar
planets.
