  The Giant Radio Array for Neutrino Detection (GRAND) aims at detecting
ultra-high energy extraterrestrial neutrinos via the extensive air showers
induced by the decay of tau leptons created in the interaction of neutrinos
under the Earth's surface. Consisting of an array of $\sim10^5$ radio antennas
deployed over $\sim 2\times10^5\,\rm {km}^2$, GRAND plans to reach, for the
first time, an all-flavor sensitivity of $\sim1.5\times10^{-10} \,\rm GeV\,
cm^{-2} \,s^{-1}\, sr^{-1}$ above $5\times10^{17}$ eV and a sub-degree angular
resolution, beyond the reach of other planned detectors. We describe here
preliminary designs and simulation results, plans for the ongoing, staged
approach to the construction of GRAND, and the rich research program made
possible by GRAND's design sensitivity and angular resolution.
