High precision predictions for e+e- Colliders

In this talk I will briefly review the physics program of planned e+e- colliders. I will focus on certain aspects of the top physics program of these machines to determine the properties and couplings of the top quark to high precision. Precision knowledge of the top quark serves as a telescope for new physics for scales of up to 100 TeV.  The talk includes both continuum production of top quarks as well as the production at very low velocities very near to the top threshold, describing techniques of fixed-order perturbative calculations in the SM as well as resummation of large logarithms close to the threshold and their combination. I will also briefly mention the connection to automated tools for precision simulations of SM processes for e+e- colliders.