  We present the result of an experiment to measure the electric dipole moment
(EDM) of the neutron at the Paul Scherrer Institute using Ramsey's method of
separated oscillating magnetic fields with ultracold neutrons (UCN). Our
measurement stands in the long history of EDM experiments probing physics
violating time reversal invariance. The salient features of this experiment
were the use of a Hg-199 co-magnetometer and an array of optically pumped
cesium vapor magnetometers to cancel and correct for magnetic field changes.
The statistical analysis was performed on blinded datasets by two separate
groups while the estimation of systematic effects profited from an
unprecedented knowledge of the magnetic field. The measured value of the
neutron EDM is $d_{\rm n} = (0.0\pm1.1_{\rm stat}\pm0.2_{\rm
sys})\times10^{-26}e\,{\rm cm}$.
