  The Fermi Constant, G_F, describes the strength of the weak force and is
determined most precisely from the mean life of the positive muon, tau_mu.
Advances in theory have reduced the theoretical uncertainty on G_F as
calculated from tau_mu to a few tenths of a part per million (ppm). Until
recently, the remaining uncertainty on G_F was entirely experimental and
dominated by the uncertainty on tau_mu. We report the MuLan collaboration's
recent 1.0 ppm measurement of the positive muon lifetime. This measurement is
over a factor of 15 more precise than any previous measurement, and is the most
precise particle lifetime ever measured. The experiment used a time-structured
low-energy muon beam and an array of plastic scintillators read-out by waveform
digitizers and a fast data acquisition system to record over 2 times 10^{12}
muon decays. Two different in-vacuum muon-stopping targets were used in
separate data-taking periods. The results from these two data-taking periods
are in excellent agreement. The combined results give
tau_{mu^+}({MuLan})=2196980.3(2.2) ps. This measurement of the muon lifetime
gives the most precise value for the Fermi Constant: G_F({MuLan}) = 1.1663788
(7) \times 10^{-5} {GeV}^{-2} (0.6 ppm). The lifetime is also used to extract
the mu^-p singlet capture rate, which determines the proton's weak induced
pseudoscalar coupling g_P.
