  Measurements of top quark production at $e^+e^-$ colliders can provide a leap
in precision in our knowledge of top quark properties and open a new window on
physics beyond the Standard Model. In this contribution the top quark physics
prospects of linear colliders is reviewed. Progress in detailed full-simulation
studies is reported for the highlights of the program. We present the prospects
for a measurement of the top quark mass and width in a scan of the beam energy
through the pair production threshold, and discuss new studies of alternative
measurements in continuum production, which are also capable of a precise
determination of the mass in a rigorously defined mass scheme. A precision of
50 MeV on the $\overline{MS}$ mass is expected when taking into account the
dominant systematic uncertainties. Another key measurement is the study of the
top quark couplings to electroweak gauge bosons, where form factors can be
determined to 1% precision, an order of magnitude better than those from the
full LHC program. New results extend the prospects to different center-of-mass
energies and to CP violating form factors. Finally, new studies are presented
indicating the possibility to detect Flavour Changing Neutral Current decays of
the top quark at linear colliders, such as the decay $t \rightarrow cH$, to a
branching ratio of $BR(t\rightarrow cH) \sim 10^{-5}$.
