  The host stars of extrasolar planets tend to be metal-rich. We have examined
the data for these stars for evidence of trends in other galactic parameters,
without success. However, several ESP hosts are likely to be members of the
thick disk population, indicating that planet formation has occurred throughout
the full lifetime of the Galactic disk. We briefly consider the radial
metallicity gradient and age-metallicity relation of the Galactic disk, and
complete a back-of-the envelope estimate of the likely number of solar-type
stars with planetary companions with 6 < R < 10 kpc.
