  The program WTO, which is designed for computing cross sections and other
relevant observables in the $e^+e^-$ annihilation into four fermions, is
described. The various quantities are computed over both a completely inclusive
experimental set-up and a realistic one, i.e. with cuts on the final state
energies, final state angles, scattering angles and final state invariant
masses. Initial state QED corrections are included by means of the structure
function approach while final state QCD corrections are applicable in their
{\it naive} formulation. A gauge restoring mechanism is included according to
the Fermion-Loop scheme. The program structure is highly modular and particular
care has been devoted to computing efficiency and speed.
