  We present the current expectations for the design and physics program of an
e+e- linear collider of center of mass energy 500 GeV -- 1 TeV. We review the
experiments that would be carried out at this facility and demonstrate its key
role in exploring physics beyond the Standard Model over the full range of
theoretical possibilities. We then show the feasibility of constructing this
machine, by reviewing the current status of linear collider technology and by
presenting a precis of our `zeroth-order' design.
