  Microlensing is the most promising method to study the statistical frequency
of extra-solar planets orbiting typical (random) stars in the Milky Way, even
those several kiloparsecs from Earth. The lensing zone corresponds to orbital
separations of a few times the Earth-Sun distance (AU) -- a good match to many
planets in our own Solar System -- and the probability of detection is a rather
weak function of planetary mass. Microlensing is thus a perfect complement to
radial velocity and astrometric techniques that allow the detailed study of
nearby planets with larger masses and smaller orbital separations. This report
forms Appendix C of the Final Report of the European Southern Observatory (ESO)
Working Group on the Detection of Extrasolar Planets, which contains
recommendations to ESO for designing a competitive strategy in the field of
extrasolar planets. The full report is available from ESO as document
SPG-VLTI-97/002.
