  We review the relation between four-dimensional global conformal blocks and
field propagation in ${\rm AdS_5}$. Following the standard argument that
marginal perturbations should backreact in the geometry, we turn to the study
of scalar fields in the generic Kerr-${\rm AdS_5}$ geometry. On one hand, the
result for scattering coefficients can be obtained exactly using the
isomonodromy technique, giving exact expressions in terms of $c=1$ chiral
conformal blocks. On the other hand, one can use the analogy between the scalar
field equations to the Level 2 null field Ward identity in two dimensional
Liouville field theory to write approximate expressions for the same
coefficients in terms of semi-classical chiral Liouville conformal blocks.
Surprisingly, the conformal block thus constructed has a well-behaved
interpretation in terms of Liouville vertex operators.
