The near-Earth asteroids (NEAs) are a population of objects on orbits that pass near that of the Earth. Many NEAs are attractive targets for spacecraft missions, and NEAs are also important because some of them will eventually hit Earth. Both future NEA missions and the impact hazard motivate understanding the sizes, shapes, surface properties, and trajectories of as many objects as possible.
The techniques of radar astronomy provide a way to characterize a representative sample of the NEA population. I will review these techniques and describe some recent radar results, focusing on spacecraft targets and objects with future close encounters with Earth.