  There is a chance that singleton fields, that in the context of strings and
membranes have been regarded as topological gauge fields that can interact only
at the boundary of anti-De Sitter space, at spatial infinity, may have a more
physical manifestation as costituents of massless fields in space time. The
composite character of massless fields is expressed by field - current
identities that relate ordinary massless field operators to singleton currents
and stress-energy tensors. Naive versions of such identities do not make sense,
but when the singletons are described in terms of dipole structures, then such
constructions are at least formally possible. The new proposal includes and
generalizes an early composite version of QED, and includes quantum gravity,
super gravity and models of QCD. Unitarity of such theories is conjectural.
