  We elaborate on the ambient space approach to boundary values of $AdS_{d+1}$
gauge fields and apply it to massless fields of mixed-symmetry type. In the
most interesting case of odd-dimensional bulk the respective leading boundary
values are conformal gauge fields subject to the invariant equations. Our
approach gives a manifestly conformal and gauge covariant formulation for these
fields. Although such formulation employs numerous auxiliary fields, it comes
with a systematic procedure for their elimination that results in a more
concise formulation involving only a reasonable set of auxiliaries, which
eventually (at least in principle) can be reduced to the minimal formulation in
terms of the irreducible Lorentz tensors. The simplest mixed-symmetry field,
namely, the rank-3 tensor associated to the two-row Young diagram, is
considered in some details.
