  The discovery of close orbiting extrasolar giant planets led to extensive
studies of disk planet interactions and the forms of migration that can result
as a means of accounting for their location. Early work established the type I
and type II migration regimes for low mass embedded planets and high mass gap
forming planets respectively. While providing an attractive means of accounting
for close orbiting planets intially formed at several AU, inward migration
times for objects in the earth mass range were found to be disturbingly short,
making the survival of giant planet cores an issue. Recent progress in this
area has come from the application of modern numerical techniques which make
use of up to date supercomputer resources. These have enabled higher resolution
studies of the regions close to the planet and the initiation of studies of
planets interacting with disks undergoing MHD turbulence. This work has led to
indications of how the inward migration of low to intermediate mass planets
could be slowed down or reversed. In addition, the possibility of a new very
fast type III migration regime, that can be directed inwards or outwards, that
is relevant to partial gap forming planets in massive disks has been
investigated.
