  We present a program to calculate the total cross section for top-quark pair
production in hadronic collisions. The program takes into account recent
theoretical developments such as approximate next-to-next-to-leading order
perturbative QCD corrections and it allows for studies of the theoretical
uncertainty by separate variations of the factorization and renormalization
scales. In addition it offers the possibility to obtain the cross section as a
function of the running top-quark mass. The program can also be applied to a
hypothetical fourth quark family provided the QCD couplings are standard.

High Energy Physics - Phenomenology