  We calculate (g-2)/2 of the muon, by improving the determination of the
hadronic vacuum polarisation contribution, a_mu^{had,LO}, and its
uncertainties. The different e+e- data sets for each exclusive (and the
inclusive) channel are combined in order to obtain the optimum estimate of the
cross sections and their uncertainties. QCD sum rules are evaluated in order to
resolve an apparent discrepancy between the inclusive data and the sum of the
exclusive channels. We conclude a_mu^{had,LO}=(683.1 +- 5.9_{exp} +- 2.0_{rad})
10^{-10} which, when combined with the other contributions to (g-2)/2, is about
3 sigma below the present world average measurement.
