  We review recent progress on the information paradox. We explain why
exponentially small correlations in the radiation emitted by a black hole are
sufficient to resolve the original paradox put forward by Hawking. We then
describe a refinement of the paradox that makes essential reference to the
black-hole interior. This analysis leads to a broadly-applicable physical
principle: in a theory of quantum gravity, a copy of all the information on a
Cauchy slice is also available near the boundary of the slice. This principle
can be made precise and established -- under weak assumptions, and using only
low-energy techniques -- in asymptotically global AdS and in four dimensional
asymptotically flat spacetime. When applied to black holes, this principle
tells us that the exterior of the black hole always retains a complete copy of
the information in the interior. We show that accounting for this redundancy
provides a resolution of the information paradox for evaporating black holes
and, conversely, that ignoring this redundancy leads to paradoxes even in the
absence of black holes. We relate this perspective to recent computations of
the Page curve for holographic CFTs coupled to nongravitational baths. But we
argue that such models may provide an inaccurate picture of the rate at which
information can be extracted from evaporating black holes in asymptotically
flat space. We discuss large black holes dual to typical states in AdS/CFT and
the new paradoxes that arise in this setting. These paradoxes also extend to
the eternal black hole. They can be resolved by assuming that the map between
the boundary CFT and the black-hole interior is state dependent. We discuss the
consistency of state-dependent bulk reconstructions. We conclude by examining
the viability of arguments for firewalls, fuzzballs and other kinds of
structure at the horizon.
