  In this chapter, we present a scattering-amplitudes perspective on
supergravity, and describe its application to the study of ultraviolet
properties of supergravity theories at high loop orders. The basic on-shell
tools that make such calculations feasible are reviewed, including generalized
unitarity, color-kinematics duality, and the double-copy construction. We also
outline the web of theories connected by the double copy. The results of
various calculations of potential ultraviolet divergences are summarized. These
include puzzling enhanced ultraviolet cancellations, for which no
symmetry-based understanding currently exists, showing that there is much more
to learn about the ultraviolet properties of supergravity theories. We finally
comment on future calculations that should help resolve the puzzles.
