Particle physics probes of extra spacetime dimensions

The possibility that spacetime extends beyond the familiar 3 + 1 dimensions has intrigued physicists for a century. The consequences of a dimensionally richer spacetime would be profound. Recently, new theories with higher-dimensional spacetimes have been developed to resolve the hierarchy problem in particle physics. The distinct predictions of these scenarios allow experiment to probe the existence of extra dimensions in new ways. We review the conceptual framework of these scenarios, their implications in collider and short-range gravity experiments, and their astrophysical and cosmological effects, as well as the constraints placed on them by current data.