  Slowly evolving horizons are trapping horizons that are "almost" isolated
horizons. This paper reviews their definition and discusses several spacetimes
containing such structures. These include certain Vaidya and Tolman-Bondi
solutions as well as (perturbatively) tidally distorted black holes. Taking
into account the associated mass scales, they also suggest that slowly evolving
horizons are the norm rather than the exception in astrophysical processes that
involve stellar-scale black holes.
