  Moderately close binaries are a special class of targets for planet searches.
  From a theoretical standpoint, their hospitality to giant planets is
uncertain and debated. From an observational standpoint, many of these systems
present technical difficulties for precise radial-velocity measurements and
classical Doppler surveys avoid them accordingly. In spite of these adverse
factors, present data support the idea that giant planets residing in binary
and hierarchical systems provide unique observational constraints on the
processes of planet formation and evolution. The interest and the importance of
including various types of binary stars in extrasolar planet studies have thus
grown over time and significant efforts have recently been put into: (i)
searching for stellar companions to the known planet-host stars using direct
imaging, and (ii) extending Doppler planet searches to spectroscopic and
moderately close visual binaries. In this contribution we review the
observational progresses made over the past years to detect and study
extrasolar planets in binary systems, putting special emphasis on the two
developments mentioned above.
