  We are still in the early days of exoplanet discovery. Astronomers are
beginning to model the atmospheres and interiors of exoplanets and have
developed a deeper understanding of processes of planet formation and
evolution. However, we have yet to map out the full complexity of multi-planet
architectures or to detect Earth analogues around nearby stars. Reaching these
ambitious goals will require further improvements in instrumentation and new
analysis tools. In this chapter, we provide an overview of five observational
techniques that are currently employed in the detection of exoplanets: optical
and IR Doppler measurements, transit photometry, direct imaging, microlensing,
and astrometry. We provide a basic description of how each of these techniques
works and discuss forefront developments that will result in new discoveries.
We also highlight the observational limitations and synergies of each method
and their connections to future space missions.
