  We propose a method for matching the next-to-leading order (NLO) calculation
of a given QCD process with a parton shower Monte Carlo (MC) simulation. The
method has the following features: fully exclusive events are generated, with
hadronization according to the MC model; total exclusive rates are accurate to
NLO; NLO results for distributions are recovered upon expansion in $\alpha_S$;
hard emissions are treated as in NLO computations while soft/collinear
emissions are handled by the MC simulation, with the same logarithmic accuracy
as the MC; and matching between the hard- and soft/collinear-emission regions
is smooth. A fraction of events with negative weight is generated, but
unweighting remains possible with reasonable efficiency. The method is
clarified using a simple toy model, and illustrated by application to the
hadroproduction of W$^+$W$^-$ pairs.
