  The Sudbury Neutrino Observatory (SNO) was a heavy water Cerenkov detector
designed to solve the long-standing ``solar neutrino problem''; a discrepancy
between the measured and predicted flux of electron-flavour solar neutrinos.
SNO measured the rate of charged-current and neutral-current reactions of
neutrinos in heavy water and was able to demonstrate that neutrinos from the
Sun, produced in the electron flavour eigenstate, undergo flavour change on
their way to the Earth, thus resolving the solar neutrino problem. The
experiment was conducted in three phases, differing by the method for measuring
the neutral current rate. This short paper summarizes results from the third
phase of the experiment, which used an array of 36 strings of proportional
counters filled with $^3$He to detect neutrons from the neutral-current
reaction. When the data from the three phases is combined with solar and the
KamLAND neutrino oscillation experiments, the resulting limits on the solar
neutrino mixing angle and mass-squared difference are $\theta_{12} =
34.4^{+1.3}_{-1.2}$ degrees and $\Delta m_{12}^2 =7.59^{+0.19}_{-0.21}\times
10^{-5}$eV$^2$, respectively.
